Optical connector, optical communication apparatus, and optical cable

Abstract

By using this optical cable comprising a removable optical connector, usability of a communication system which connects devices distant from each other is improved.　An optical connector (10A) according to the present technology comprises a housing (11), a bend part (13), and reflection parts (14, 15). The bend part (13) bends input light inputted from a transmission-side outside connector transmission path (16) disposed on one end side of the housing to thereby emit the resulting light to a space formed inside the housing. The bending angle by the bend part is set at an angle which enables bent light, which is emitted from the bend part to the space, to be transmitted toward the reflection parts. The reflection parts (14, 15) are provided inside the housing. The reflection parts reflect the bent light emitted from the bend part to the space. The reflection angles of the reflection parts are set at angles which enables reflection light, which is reflected from the reflection parts, to be transmitted via the bend part toward a reception-side outside connector transmission path (19) disposed on said one end side of the housing.

Description

Optical connector, optical communication device and optical cable

[0001] The present technology relates to an optical connector, an optical communication device, and an optical cable, and more particularly to an optical connector and the like that has a function of returning light when disconnected.

[0002] 2. Description of the Related Art There are known communication systems that connect devices over a large distance using optical cables with detachable optical connectors. Improved usability of such communication systems is desirable.

[0003] Japanese Patent Application Laid-Open No. 5-273478 Japanese Patent Application Laid-Open No. 2003-014991 International Publication No. 2017 / 056889

[0004] An object of the present technology is to enable improved usability of a communication system that connects devices that are far apart using an optical cable equipped with a detachable optical connector.

[0005] The concept of this technology is an optical connector comprising: a housing; a bending portion that bends one or more transmission light beams input from one or more transmission-side connector external transmission paths located on one end side of the housing and emits the light beams into a space formed within the housing; and a reflecting portion that is provided within the housing and reflects the one or more transmission light beams emitted from the bending portion into the space, wherein a bending angle of the bending portion is set to an angle at which the one or more transmission light beams are transmitted toward the reflecting portion, and a reflection angle of the reflecting portion is set to an angle at which the one or more transmission light beams are transmitted via the bending portion toward one or more reception-side connector external transmission paths located on the one end side of the housing and paired with the one or more transmission-side connector external transmission paths, respectively.

[0006] The optical connector of the present technology includes a housing, a bending portion, and a reflecting portion. The bending portion bends one or more transmission light beams input from one or more transmission-side connector external transmission paths located at one end of the housing and outputs them into a space formed within the housing. Here, the bending angle of the bending portion is set to an angle at which the one or more transmission light beams are transmitted toward the reflecting portion.

[0007] The reflector is provided within the housing. The reflector reflects one or more transmission light beams emitted into space from the bent portion. Here, the reflection angle of the reflector is set to an angle at which the one or more transmission light beams are transmitted via the bent portion toward one or more reception-side external connector transmission paths located at one end side of the housing and paired with one or more transmission-side external connector transmission paths, respectively.

[0008] For example, when no other optical connector is mated to the other end of the housing, an unmated optical path is established that transmits one or more transmitted light beams toward a transmission path outside the receiving connector, and when another optical connector is mated to the other end of the housing, an engaged optical path is established in cooperation with the other optical connector that transmits one or more transmitted light beams from the other end toward the other optical connector and transmits one or more received light beams from the other optical connector toward a transmission path outside the receiving connector. This allows optical transmission between the other connector and the other optical connector when the other optical connector is mated to the other end of the housing.

[0009] Furthermore, for example, each intra-optical connector transmission path set may be configured by a plurality of intra-transmission paths in a transmitting connector that transmit a plurality of transmission light beams input from a plurality of transmission paths outside the transmitting connector, and a plurality of intra-receiving connector transmission paths each paired with one of the plurality of intra-transmission paths in the transmitting connector. In this case, for example, each intra-optical connector transmission path set may be paired in a correspondence relationship according to the identifier of the optical connector.

[0010] Furthermore, for example, the reflecting portion may be configured with one or more reflecting surfaces, and the bending portion may be configured with a prism or a reflecting surface. Furthermore, for example, the transmission path outside the receiving connector may be a transmission path dedicated to detection that is not used for communicating actual data.

[0011] In this way, in this technology, when no other optical connector is fitted to the other end of the housing, the light input from the transmission path outside the transmitting connector is returned to the transmission path outside the receiving connector via the bending section and the reflecting section, making it possible to detect whether the optical connector is connected or disconnected.

[0012] Another concept of the present technology is a self-device optical connector including: a housing; a bending portion that bends one or more transmission light beams input from one or more transmission paths in a transmitting device located on one end side of the housing and emits the light into a space formed within the housing; and a reflecting portion that is provided within the housing and reflects the one or more transmission light beams emitted from the bending portion into the space, wherein a bending angle of the bending portion is set to an angle at which the one or more transmission light beams are transmitted toward the reflecting portion, and a reflection angle of the reflecting portion is set to an angle at which the one or more transmission light beams are transmitted via the bending portion toward one or more transmission paths in a receiving device located on the one end side of the housing and paired with the one or more transmission paths in the transmitting device; one or more transmitting portions that transmit the transmission light beams to the one or more transmission paths in the transmitting device, respectively; and one or more receiving portions that receive the one or more transmission light beams transmitted through the one or more transmission paths in the receiving device as one or more reception light beams for detection. and a control unit that detects connection relationship information based on a reception state of the one or more detection-use received lights in the one or more receiving units.

[0013] The optical communication device of the present technology includes a local optical connector, one or more transmitters, one or more receivers, and a controller, wherein the local optical connector includes a housing, a bending portion, and a reflecting portion.

[0014] The optical connector for the device itself includes a housing, a bending portion, and a reflecting portion. One or more transmission light beams input from one or more transmission paths within the transmitting device located at one end of the housing are bent by the bending portion and emitted into a space formed within the housing. Here, the bending angle of the bending portion is set to an angle at which the one or more transmission light beams are transmitted toward the reflecting portion.

[0015] The reflecting section is provided within the housing. The reflecting section reflects one or more transmission light beams emitted into space from the bent section. Here, the reflection angle of the reflecting section is set to an angle at which the one or more transmission light beams are transmitted via the bent section toward one or more transmission paths in the receiving device that are located at one end side of the housing and paired with one or more transmission paths in the transmitting device.

[0016] One or more transmitters transmit transmitted light beams to one or more transmission paths within the transmitting device. One or more receivers receive one or more transmitted light beams transmitted through one or more transmission paths within the receiving device as one or more received light beams for detection. Then, a control unit detects connection relationship information based on the reception state of the one or more received light beams for detection at the one or more receivers.

[0017] For example, the reception state may be a state based on the connection relationship between the optical connector of the own device and the optical connector of the target communication device.

[0018] Furthermore, for example, in a non-mated state where another optical connector is not mated on the other end side of the housing, a non-mated optical path is established that transmits one or more transmission light beams transmitted from one or more transmitters toward a transmission path within the receiving device, and the one or more receivers receive the one or more transmission light beams as one or more detection-use received light beams, and in a mated state where the other optical connector is mated on the other end side of the housing, a mated optical path is established in cooperation with the other optical connector that transmits one or more transmission light beams transmitted from the one or more transmitters from the other end side toward the other optical connector. In this case, for example, one or more light beams input from the other optical connector to the optical connector of the own device from the other optical connector via the mated optical path may be transmitted toward a transmission path within the receiving device.

[0019] Furthermore, for example, the own optical connector may be configured to be mechanically and optically connectable to a target communication device optical connector configured to be connectable to one optical cable of the optical intermediate connectors via one or more optical intermediate connectors including at least one optical cable. In this case, for example, the one or more optical intermediate connectors may each have an intermediate connector optical connector at one end and the other end, and the control unit may be configured to detect the connection relationship information based on a reception state at one or more receiving units of the detection-use received light, which is light returned by the unmated-state optical path as the transmitted light, when a non-mated-state optical path is established in either the own optical connector or the intermediate connector optical connector provided at the other end of the one or more optical intermediate connectors.

[0020] Furthermore, for example, the self-device optical connector may be configured to be mechanically and optically connectable to a target communication device optical connector that is configured to be mechanically and optically connectable to a first optical cable of one or more optical intermediate connection devices or a second optical cable different from the first optical cable via connection with the intermediate connection device optical connector of a first optical cable of one or more optical intermediate connection devices that includes at least an optical cable.

[0021] Furthermore, for example, the optical connector of the own device may be configured to be indirectly connectable to the optical connector of the communication device to be connected via an optical intermediate connection device including at least one optical cable.

[0022] Furthermore, for example, the own-device optical connector may be configured to be indirectly connectable to the target communication device optical connector via connection to the intermediate connection device optical connector of one optical cable of one or more optical intermediate connection devices including at least one optical cable configured to be connectable to the own-device optical connector.

[0023] Furthermore, for example, the connection relationship information may be detachment information indicating detachment between two optical connectors that should be mated among a plurality of optical connectors between the optical connector of the own device and the optical connector of the communication device to be connected. In this case, for example, the connection relationship information may be detachment position information indicating the position of detachment.

[0024] Also, for example, one or more transmitters may be paired with one or more receivers, and each transmitter / receiver set may be formed by the paired transmitter and receiver, and the control unit may detect connection relationship information for each transmitter / receiver set.

[0025] Furthermore, for example, the control unit may detect, as the connection relationship information, path information indicating which of the multiple receiving units received each of the multiple transmission light beams transmitted from each of the multiple transmitters. In this case, for example, the control unit may detect, as the connection relationship information, identifier information that identifies the connector in a connected state immediately before the detachment position based on the path information. In this case, for example, the control unit may detect, as the connection relationship information, detachment position information that indicates the detachment position based on the path information.

[0026] Furthermore, for example, the connection relationship information may be disconnection information indicating a disconnection between one or more transmitters and an optical connector of a communication device to be connected. Also, for example, the connection relationship information may include detachment position information indicating a location of detachment, and disconnection information indicating a disconnection between one or more transmitters and an optical connector of a communication device to be connected.

[0027] In this way, this technology detects connection relationship information based on one or more detection received lights in one or more receiving units, making it possible to detect, for example, detachment information indicating a detachment between two optical connectors, or disconnection information indicating a disconnection between one or more transmitting units and the optical connector of the communication device to be connected.

[0028] and a second optical connector provided on the other end side of the one or more intra-optical-cable transmission line sets, the second optical connector comprising: a housing; and a bending portion that bends one or more transmission light beams that are input to the first optical connector from one or more transmission-side external optical-cable transmission lines located on the one end side of the housing and received via the transmission-side internal optical-cable transmission line, and outputs the bent light beams into a space formed within the housing; and a reflecting portion that is provided within the housing and reflects the one or more transmission light beams that have been output from the bending portion into the space, the bending angle of the bending portion being set to an angle at which the one or more transmission light beams are transmitted toward the reflecting portion, The optical cable has a reflection angle of the reflecting portion set to an angle at which the one or more transmitted light beams are transmitted via the bending portion toward one or more receiving-side optical cable external transmission paths that are located on the one end side of the housing and that are paired with the one or more transmitting-side optical cable external transmission paths.

[0029] 1 is a diagram showing an example of the configuration of an optical connector (a structure in which the bent portion is a prism and there are two reflective surfaces as a reflective portion); FIG. 2 is a diagram showing a simplified perspective view of a receptacle provided in a device and a plug provided at the end of an optical cable; FIG. 3 is a diagram showing the overall configuration of an optical cable; FIG. 4 is a diagram showing a state in which a plug is mated with a receptacle; FIG. 5 is a diagram showing a state in which a plug on one end of an optical cable is mated with a receptacle of device A and the plug on the other end of the optical cable is mated with a receptacle of device B; FIG. 6 is a diagram showing a disengaged state in which the plug on one end of an optical cable is mated with a receptacle of device A and the plug on the other end of the optical cable is not mated; FIG. 7 is a diagram showing another example of the configuration of an optical connector (a structure in which the bent portion is a prism and there is one reflective surface as a reflective portion); FIG. 8 is a diagram showing a state in which a plug is mated with a receptacle; 1 is a diagram showing a state in which a plug is mated with a receptacle. FIG. 2 is a diagram showing a state in which an optical cable having a plug on one end mated with a receptacle of device A and the other end mated with a receptacle of device B. FIG. 3 is a diagram showing a detached state in which an optical cable having a plug on one end mated with a receptacle of device A and the plug on the other end mated is not mated. FIG. 4 is a diagram showing another example of the configuration of an optical connector (a structure in which the bent portion is a prism, there are two reflective surfaces as a reflective portion, and a detection-dedicated transmission path is added). FIG. 5 is a diagram showing a state in which a plug is mated with a receptacle. FIG. 6 is a diagram showing another example of the configuration of an optical connector (a structure in which the bent portion is two reflective surfaces, there are two reflective surfaces as a reflective portion). FIG. 7 is a diagram showing a state in which a plug is mated with a receptacle. FIG. 8 is a diagram showing another example of the configuration of an optical connector (a structure in which light is returned via a path according to an identifier when removed). FIG. 9 is a diagram showing an example of path information. FIG. 10 is a diagram showing an example in which a transmission path set number identification optical signal is a pulse signal. FIG. 11 is a diagram showing an example of the configuration of a relay adapter. 1 is a diagram showing a state in which a plug is fitted into one end of a relay adapter and a plug is not fitted into the other end of the relay adapter. 2 is a diagram showing a state in which a plug is fitted into one end of the relay adapter and a plug is also fitted into the other end of the relay adapter. 3 is a diagram showing an example of the configuration of an optical communication system (a system in which two devices are connected by one optical cable).1 is a diagram collectively showing each transmission path in an optical communication system. FIG. 1 is a diagram showing another configuration example of an optical communication system (a system in which two devices are connected by two optical cables connected in series). FIG. 2 is a diagram showing another configuration example of an optical communication system (a system in which two devices are connected by a plurality of optical cables connected via relay adapters). FIG. 3 is a diagram showing another configuration example of an optical communication system (a system in which a disconnection is detected using an optical circulator). FIG. 4 is a diagram showing another configuration example of an optical communication system (a system in which a detection transmission path is provided). FIG. 5 is a flowchart showing an example of a processing procedure for connection detection processing and subsequent communication processing, etc. in an optical communication system. FIG. 6 is a flowchart showing another example of a processing procedure for connection detection processing and subsequent communication processing, etc. in an optical communication system. FIG. 7 is a flowchart showing yet another example of a processing procedure for connection detection processing and subsequent communication processing, etc. in an optical communication system. FIG. 8 is a flowchart showing an example of connection detection processing (an example in which only disconnection is determined). FIG. 9 is a flowchart showing an example of connection detection processing (an example in which disconnection of the transmitting side transmission path and the receiving side transmission path is not determined individually). FIG. 10 is a flowchart showing another example of connection detection processing (an example in which disconnection of the transmitting side transmission path and the receiving side transmission path is determined individually). FIG. 1 is a flowchart showing another example of connection detection processing (an example in which disconnections in the transmitting side transmission line and the receiving side transmission line are not determined individually). FIG. 2 is a flowchart showing another example of connection detection processing (an example in which disconnections in the transmitting side transmission line and the receiving side transmission line are determined individually). FIG. 3 is a flowchart showing an example of connection detection processing (an example in which a dedicated detection transmission line is provided and only disconnection is determined). FIG. 4 is a flowchart showing another example of connection detection processing (an example in which a dedicated detection transmission line is provided and disconnections in the transmitting side transmission line and the receiving side transmission line are not determined individually). FIG. 5 is a flowchart showing another example of connection detection processing (an example in which a dedicated detection transmission line is provided and disconnections in the transmitting side transmission line and the receiving side transmission line are determined individually). FIG. 6 is a flowchart showing an example of communication processing. FIG. 7 is a diagram showing an example of a specific configuration for implementing a first technique for identifying a disconnection position (a technique in which pulsed light is used to identify the disconnection position from the delay time of returned light). FIG. 8 is a flowchart showing an example of a processing procedure when identifying a disconnection position (first technique).1 is a diagram showing an example of a specific configuration for implementing a second method for identifying a disconnection position (a method for using continuous light to identify a disconnection position from the delay time of returned light); FIG. 2 is a flowchart showing an example of a processing procedure for identifying a disconnection position (second method); FIG. 3 is a diagram showing another example of a specific configuration for implementing a second method for identifying a disconnection position (a method for using continuous light to identify a disconnection position from the delay time of returned light); FIG. 4 is a flowchart showing another example of a processing procedure for identifying a disconnection position (second method); FIG. 5 is a diagram showing an example of a specific configuration for implementing a third method for identifying a disconnection position (a method for identifying a disconnection position using an identifier (ID) unique to the other end connector held by a connected target device); FIG. 6 is a diagram showing an example of path information acquired by a receptacle or a relay adapter, and an example of path information acquired by an optical cable; FIG. 7 is a diagram showing an example of relationship information indicating the correspondence between connection points, their distances, and identifiers; FIG. 2 is a block diagram illustrating an example of the hardware configuration of a computer.

[0030] Modes for carrying out the invention (hereinafter referred to as "embodiments") will be described below. The description will be made in the following order. 1. Embodiments 1-1. Example of optical connector configuration 1-1-1. Structure in which the bent portion is a prism and has two reflecting surfaces as the reflecting portion 1-1-2. Structure in which the bent portion is a prism and has one reflecting surface as the reflecting portion 1-1-3. Structure in which the bent portion is a prism and has one reflecting surface as the reflecting portion, and a detection-dedicated transmission path is added 1-1-4. Structure in which the bent portion is a prism and has two reflecting surfaces as the reflecting portion, and a detection-dedicated transmission path is added 1-1-5. Structure in which the bent portion is two reflecting surfaces and has two reflecting surfaces as the reflecting portion 1-1-6. Structure in which light is returned via a path according to an identifier when detached 1-1-7. Structure in which a relay adapter is used for cable connection 1-2. 1-2-1. Configuration examples of optical communication systems 1-2-1. Structure in which two devices are connected with one optical cable 1-2-2. Structure in which two devices are connected with multiple optical cables 1-2-3. Structure in which two devices are connected with multiple optical cables connected by relay adapters 1-2-4. Structure in which disconnection is detected using an optical circulator 1-2-5. Structure in which a detection transmission path is provided 1-3. Example of processing procedure including connection detection processing and communication processing, etc. 1-3-1. Connection detection processing 1-3-2. Communication processing 1-4. Identifying the separation position 1-4-1. Using pulsed light (optical signal), identifying the separation position from the delay time of the returned light 1-4-2. Using continuous light (optical signal), identifying the separation position from the delay time of the returned light 1-4-3. Identifying the separation position using an identifier (ID) unique to the connection point 1-5. Specific examples in which this technology is applied 1-6. Processing by software 2. Modified examples

[0031] 1. Embodiments> "1-1. Configuration example of optical connector" "1-1-1. Structure in which the bending portion is a prism and the reflecting portion has two reflective surfaces" Fig. 1(a1) shows a configuration example of a receptacle 10A as an optical connector provided in a device, and Fig. 1(a2) shows a configuration example of a plug 30A as an optical connector provided in an optical cable 30Aa that is fitted into this receptacle 10A. The plug 30A is a plug (first optical connector) provided on one end of the optical cable 30Aa, and a similar plug (second optical connector) is provided on the other end of the optical cable 30Aa. An optical cable main body 30A" is present between the plug 30A and the plug on the other end.

[0032] Here, the device equipped with receptacle 10A is defined as device A, the device connected to device A via an optical cable equipped with plug 30A is defined as device B, and the transmitting side and receiving side are defined as seen from device A. In this case, light transmitted from device A to device B (light transmitted by device A) is defined as transmitted light, and the transmission path transmitting this transmitted light is the transmitting side transmission path (first transmission path). Furthermore, light transmitted from device B to device A (light transmitted by device B) is defined as received light, and the transmission path transmitting this received light is the receiving side transmission path (second transmission path). These definitions also apply to other optical connector configuration examples described below.

[0033] Here, the equipment has, as its equipment transmission paths, transmission paths within the connector (receptacle) that are transmission paths within the receptacle (transmission path within the transmitting connector, transmission path within the receiving connector), and transmission paths within the equipment that are transmission paths outside the receptacle (transmission path within the transmitting equipment, transmission path within the receiving equipment). Furthermore, the optical cable has, as its optical cable transmission paths, transmission paths within the connector (plug) that are transmission paths within the plugs at both ends (transmission path within the transmitting connector, transmission path within the receiving connector), and optical cable main body transmission paths that are transmission paths within the optical cable main body (transmission path within the optical cable main body transmission path, reception path within the optical cable main body transmission path). These definitions also apply to other optical connector configuration examples described later.

[0034] Fig. 2 is a simplified perspective view of a receptacle provided in a device and a plug provided at the end of an optical cable. The x-axis, y-axis, and z-axis directions shown in Fig. 1 correspond to the directions shown in Fig. 2, for example. That is, the x-axis direction corresponds to the up-down direction of the receptacle and plug, the y-axis direction corresponds to the left-right direction of the receptacle and plug, and the z-axis direction corresponds to the front-rear direction of the receptacle and plug.

[0035] 1(a1), a receptacle 10A provided in the device will be described. The receptacle 10A has a housing 11, a ferrule 12, a prism 13, a reflecting mirror 14, and a reflecting mirror 15.

[0036] The ferrule 12 is integrally formed with a lens (collimating lens) 17 for collimating light (transmission light) transmitted from a transmission path within a transmitting device (transmission path outside a transmitting connector) 16 arranged at one end of the housing 11 and transmitting the light to the prism 13, and a lens (condensing lens) 18 for condensing light input from the prism 13 and transmitting the light to a transmission path within a receiving device (transmission path outside a receiving connector) 19 arranged at one end of the housing 11. In this case, the transmission path 16 within the transmitting device constitutes a part of the transmission path (first transmission path), and the transmission path 19 within the receiving device constitutes a part of the reception path (second transmission path), and one transmission path within the transmitting device 16 and one transmission path within the receiving device 19 constitute one intra-device transmission path set.

[0037] Although FIG. 1(a1) shows one transmission path 16 and one transmission path 19 in the receiving device, a plurality of transmission paths 16 and a plurality of transmission paths 19 in the receiving device may be provided. That is, a plurality of sets of transmission paths may be provided. For example, when a plurality of sets of transmission paths are provided, the plurality of sets of transmission paths may be arranged side by side in the depth direction of FIG. 1, i.e., in the left-right direction (y-axis direction) in FIG. 2 described above. In this case, each transmission path 16 in the receiving device is paired with one of the transmission paths 19 in the receiving device, and each pair of the transmission path 16 in the receiving device and the transmission path 19 in the receiving device constitutes an intra-device transmission path set. Each intra-device transmission path set is provided corresponding to each communication channel (transmission / reception channel). In this case, receptacle 10A includes transmission lines in the transmitting optical connector corresponding to the transmission lines 16 in the transmitting device, and transmission lines in the receiving optical connector corresponding to the transmission lines 19 in the receiving device. Each transmission line in the transmitting optical connector is paired with one of the transmission lines in the receiving optical connector, and each pair of transmission lines in the transmitting optical connector and transmission line in the receiving optical connector constitutes an optical connector transmission line set.

[0038] Here, the lenses 17 and 18 may not be integral with the ferrule 12 but may be formed separately from the ferrule 12. Furthermore, the transmission path 16 in the sending device and the transmission path 19 in the receiving device may be configured by an optical waveguide such as an optical fiber, or may be configured by a spatial transmission path.

[0039] The prism 13 forms a bending portion, and bends light (transmitted light) input from the transmission path 16 inside the transmitting device, and emits the light into the space formed inside the housing 11. The bending angle is set to an angle at which the light (bent light) emitted into the space from the prism 13 is transmitted toward the reflecting mirror 14.

[0040] The reflecting surfaces of the reflecting mirrors 14 and 15 constitute a reflecting section. The reflecting mirrors 14 and 15 are formed at positions facing each other inside the other end of the housing 11. The reflection angle of the reflecting section is set to an angle at which light reflected by the reflecting section (reflected light) is transmitted via the prism 13 toward the transmission path 19 in the receiving device.

[0041] In this case, as shown in FIG. 1(b1), the reflective surface of the reflective mirror 14 is rotated by θy11 degrees from the z-axis around the y-axis as its central axis to reflect light from the prism 13 upward in the figure, and the reflective surface of the reflective mirror 15 is rotated by -θy11 degrees from the z-axis around the y-axis as its central axis to reflect light from below in the figure toward the prism 13, as shown in FIG. 1(b1). Note that in the illustrated example, the reflective surfaces of the reflective mirrors 14 and 15 are flat, but any shape may be used as long as it does not impair their function as reflectors. For example, the reflective surface of the reflective mirror 14 may be concave and the reflective surface of the reflective mirror 15 may be convex, or vice versa.

[0042] As shown in the figure, the operation of receptacle 10A will be described in a state in which plug 30A is not mated with receptacle 10A, i.e., in a disconnected state. In this case, light input from transmission path 16 within the transmitting device to ferrule 12 is collimated by lens (collimating lens) 17, then bent by prism 13 and incident on the reflective surface of lower reflecting mirror 14. Next, the light reflected by reflecting mirror 14 is incident on the reflective surface of upper reflecting mirror 15. Next, the light reflected by reflecting mirror 15 (reflected light) is bent by prism 13 and focused by lens (focusing lens) 18, and input to transmission path 19 within the receiving device as received light for detection, in this case, disconnected state detection light (disconnected state detection light).

[0043] In this way, an optical path in the non-mated state is formed, and light transmitted from transmission path 16 in the transmitting device to ferrule 12 is returned to transmission path 19 in the receiving device as received light for detection (disconnected state detection light, non-connected state detection light) via prism 13 and reflecting mirrors 14 and 15. That is, in the non-mated state where plug 30A, which is another optical connector, is not mated to the other end of housing 11, an optical path in the non-mated state is formed that transmits one or more transmitted light beams transmitted from one or more transmitters, described below, toward transmission path 19 in the receiving device, and one or more receivers receive one or more transmitted light beams as one or more received light beams for detection. This enables a device equipped with receptacle 10A to detect, as connection relationship information, that plug 30A is disconnected from receptacle 10A, or in other words, that an optical cable equipped with connector 30A is disconnected from a device equipped with receptacle 10A. In this case, the light transmitted from the transmission path 16 in the transmitting device to the ferrule 12 is not output to the outside from the other end side of the housing 11, so eye safety is also achieved.

[0044] With reference to Fig. 1(a2), a plug 30A (first optical connector) provided in the optical cable 30Aa will be described. The optical cable 30Aa has an optical cable main body transmission line set (optical cable internal transmission line set) consisting of two transmission lines as an optical cable main body transmission line (optical cable internal transmission line): a transmitting side optical cable main body transmission line (transmission line outside the transmitting side connector, transmission line inside the transmitting side optical cable) 39 and a receiving side optical cable main body transmission line (transmission line outside the receiving side connector, transmission line inside the receiving side optical cable) 36. Plugs are provided on one end and the other end of this optical cable main body transmission line set, and Fig. 1(a2) shows the plug 30A on the one end.

[0045] The plug 30A includes a housing 31, a ferrule 32, a prism 33, a reflecting mirror 34, and a reflecting mirror 35.

[0046] The ferrule 32 is integrally formed with a lens (collimating lens) 37 for collimating light (receiving light) input from a receiving-side optical cable main transmission line (transmission line outside the receiving connector) 36 arranged on the other end side of the housing 31 and inputting it to the prism 33, and a lens (condensing lens) 38 for condensing the light input from the prism 33 and inputting it to a transmitting-side optical cable main transmission line (transmission line outside the transmitting connector) 39 arranged on the other end side of the housing 31. In this case, the transmitting-side optical cable main transmission line 39 constitutes a part of the transmitting-side transmission line (first transmission line), the receiving-side optical cable main transmission line 36 constitutes a part of the receiving-side transmission line (second transmission line), and the transmitting-side optical cable main transmission line 39 and the receiving-side optical cable main transmission line 36 constitute one optical cable main transmission line set.

[0047] Although FIG. 1( a2 ) shows one transmitting-side optical cable main transmission line 39 and one receiving-side optical cable main transmission line 36, a plurality of transmitting-side optical cable main transmission lines 39 and a plurality of receiving-side optical cable main transmission lines 36 may be provided. That is, a plurality of optical cable main transmission line sets may be provided. For example, when a plurality of optical cable main transmission line sets are provided, these optical cable main transmission line sets may be arranged side by side in the depth direction of FIG. 1 , i.e., in the left-right direction (y-axis direction) of FIG. 2 described above. In this case, each transmitting-side optical cable main transmission line 39 is paired with one of the receiving-side optical cable main transmission lines 36, and each pair of the transmitting-side optical cable main transmission line 39 and the receiving-side optical cable main transmission line 36 constitutes an optical cable main transmission line set. Each optical cable main transmission line set is provided corresponding to each communication channel (transmitting and receiving channel).

[0048] Here, the lenses 37 and 38 may not be integral with the ferrule 32 but may be formed separately from the ferrule 32. Furthermore, the transmitting-side optical cable main body transmission path 39 and the receiving-side optical cable main body transmission path 36 are configured with optical waveguides such as optical fibers.

[0049] The prism 33 constitutes a bending portion, and bends the light (received light) input from the receiving-side optical cable main transmission path 36 and emits it into the space formed within the housing 31. The bending angle is set to an angle at which the light (bent light) emitted into the space from the prism 33 is transmitted toward the reflecting mirror 34.

[0050] The reflecting surfaces of the reflecting mirrors 34 and 35 constitute a reflecting portion. The reflecting mirrors 34 and 35 are formed at positions facing each other inside one end of the housing 31. The reflection angle of this reflecting portion is set to an angle at which light reflected by this reflecting portion (reflected light) is transmitted toward the transmitting-side optical cable main transmission path 39 via the prism 33.

[0051] In this case, as shown in FIG. 1(b2), the reflective surface of the reflective mirror 34 is rotated by θy31 degrees from the z-axis around the y-axis as its central axis to reflect light from the prism 33 upward in the figure, and the reflective surface of the reflective mirror 35 is rotated by -θy31 degrees from the z-axis around the y-axis as its central axis to reflect light from below in the figure toward the prism 33. In the illustrated example, the reflective surfaces of the reflective mirrors 34 and 35 are flat, but any shape may be used as long as it does not impair their function as reflectors. For example, the reflective surface of the reflective mirror 34 may be concave and the reflective surface of the reflective mirror 35 may be convex, or vice versa.

[0052] As shown in the figure, the operation of the plug 30A will be described in a state in which the plug 30A is not mated with the receptacle 10A, i.e., in a disconnected state. In this case, light input from the receiving-side optical cable main transmission path 36 to the ferrule 32 is collimated by the lens (collimating lens) 37, then bent by the prism 33 and incident on the reflective surface of the lower reflecting mirror 34. Next, the light reflected by the reflecting mirror 34 is incident on the reflective surface of the upper reflecting mirror 35. Next, the light reflected by the reflecting mirror 35 (reflected light) is bent by the prism 33 and focused by the lens (focusing lens) 38, and input to the transmitting-side optical cable main transmission path 39 as received light for detection, in this case, disconnected state detection light (disconnected state detection light).

[0053] In this way, a non-mated optical path is formed, and light transmitted from the receiving-side optical cable main body transmission path 36 to the ferrule 32 is returned as detachment state detection light (disconnection state detection light) to the transmitting-side optical cable main body transmission path 39 via the prism 33 and reflecting mirrors 34 and 35. In this case, the light transmitted from the receiving-side optical cable main body transmission path 36 to the ferrule 32 is not output to the outside from one end side of the housing 31, thereby realizing eye safety. Note that in Figures 1(a1) and 1(a2), arrows indicate the traveling direction of light, and arrows in Figure 4 and other figures shown below similarly indicate the traveling direction of light.

[0054] FIG. 3 shows the overall configuration of an optical cable 30Aa, in which the above-described plug 30A is provided at one end as a first optical connector, and a plug 30A' configured similarly to the plug 30A is provided at the other end as a second optical connector. An optical cable main body 30A" is present between the plugs 30A and 30A', and this optical cable main body 30A" includes the above-described optical cable main body transmission paths (receiving-side optical cable main body transmission path 36 and transmitting-side optical cable main body transmission path 39) as transmission paths within the optical cable. Since the plug 30A' is configured similarly to the plug 30A, detailed description thereof will be omitted. Each part of the plug 30A' is designated by a symbol obtained by adding a prime symbol to the symbol designated to each part of the plug 30A, so that the correspondence between each part of the plug 30A' and each part of the plug 30A can be clearly seen.

[0055] Furthermore, this optical cable 30Aa has a cross cable structure, in which the receiving-side optical cable main body transmission path 36 and the transmitting-side optical cable main body transmission path 39 cross midway along the optical cable main body 30A". Therefore, in this optical cable 30Aa, light that is output from the lens (condensing lens) 38 of the plug 30A and input to the transmitting-side optical cable main body transmission path 39 is output from this transmitting-side optical cable main body transmission path 39 and input to the lens (collimating lens) 37' of the plug 30A'. Also, in this optical cable 30Aa, light that is output from the lens (condensing lens) 38' of the plug 30A' and input to the receiving-side optical cable main body transmission path 36 is output from this receiving-side optical cable main body transmission path 36 and input to the lens (collimating lens) 37 of the plug 30A.

[0056] 4 shows the state in which plug 30A is mated with receptacle 10A. Although not mentioned above, receptacle 10A and plug 30A are optical connectors in which a transmission line is connected via a space. Although not shown, receptacle 10A and plug 30A preferably have an anti-reflection film provided at the interface between prism 13 and prism 33 and the space, for example, to reduce loss due to reflection at the interface when mated.

[0057] As shown in the figure, when plug 30A is fitted into receptacle 10A, it is preferable that a gap be provided between prism 13 of receptacle 10A and prism 33 of plug 30A to prevent damage to the anti-reflection coatings provided on prism 13 and prism 33. Note that it is also possible to configure the receptacle 10A so that no gap is provided between prism 13 of receptacle 10A and prism 33 of plug 30A when plug 30A is fitted into receptacle 10A.

[0058] When the plug 30A is mated with the receptacle 10A, light input to the ferrule 12 from the transmission path 16 in the receptacle 10A is collimated by the lens (collimating lens) 17, passes through the prisms 13 and 33, is collected by the lens (collimating lens) 38, and is input to the transmission path 39 in the transmission optical cable main body of the plug 30A. When the plug 30A is mated with the receptacle 10A, light input to the ferrule 32 from the reception optical cable main body transmission path 36 in the plug 30A is collimated by the lens (collimating lens) 37, passes through the prisms 33 and 13, is collected by the lens (collimating lens) 18, and is input to the transmission path 19 in the reception device of the receptacle 10A.

[0059] Thus, in the mated state in which the plug 30A is mated with the receptacle 10A, a mated optical path is formed connecting the receptacle 10A side and the plug 30A side. That is, in the mated state in which the plug 30A, which is another optical connector, is mated with the other end of the housing 11, a mated optical path is established in cooperation with the plug 30A, which is another optical connector, for transmitting one or more transmitted light beams transmitted from one or more transmitters (described later) from the other end to the plug 30A, which is another optical connector. Then, one or more light beams input from the plug, which is another optical connector, to the receptacle 10A, which is the optical connector of the device itself, via the mated optical path are transmitted to the receiving-side device internal transmission path 19. Therefore, the receiving-side device internal transmission path 19 functions as a receiving and detecting transmission path that serves both as a receiving transmission path for light transmitted from device B and as a receiving transmission path for received light for detection (detachment state detection light, non-connection state detection light). Here, the optical path from lens (collimating lens) 17 of receptacle 10A to lens (collimating lens) 38 of plug 30A and the optical path from lens (collimating lens) 37 of plug 30A to lens (collimating lens) 18 of receptacle 10A can be realized by the design of prisms 13 and 33.

[0060] 5 shows a state in which a receptacle 10A of device A is connected to a receptacle 10A' of device B via an optical cable 30Aa (see FIG. 3). In this case, a plug 30A provided as a first optical connector on one end of the optical cable 30Aa is mated with the receptacle 10A of device A, and a plug 30A' provided as a second optical connector on the other end of the optical cable 30Aa is mated with the receptacle 10A' of device B. Note that the receptacle 10A' has the same configuration as the receptacle 10A, and therefore a detailed description thereof will be omitted. Each part of the receptacle 10A' is designated by a symbol obtained by adding a prime symbol to the symbol designated to each part of the receptacle 10A, so that the correspondence between each part of the receptacle 10A' and each part of the receptacle 10A can be clearly seen.

[0061] 5, light input to ferrule 12 from transmission path 16 in the transmitting device on the receptacle 10A side is collimated by lens (collimating lens) 17, passes through prisms 13 and 33, is focused by lens (condensing lens) 38, and is input to transmission path 39 in the transmitting optical cable main body on the plug 30A side. Then, light output from transmission path 39 in the transmitting optical cable main body is collimated by lens (collimating lens) 37' on the plug 30A' side, passes through prisms 33' and 13', is focused by lens (condensing lens) 18', and is input to transmission path 19' in the transmitting device on the receptacle 10A' side.

[0062] 5, light input from receiving-side device internal transmission path 16' on the receptacle 10A' side to ferrule 12' is collimated by lens (collimating lens) 17', passes through prism 13' and prism 33', is focused by lens (condensing lens) 38', and is input to receiving-side optical cable main body transmission path 36 on the plug 30A' side. Light output from receiving-side optical cable main body transmission path 36 is collimated by lens (collimating lens) 37 on the plug 30A side, passes through prism 33 and prism 13, is focused by lens (condensing lens) 18, and is input to receiving-side device internal transmission path 19 on the receptacle 10A side. In this way, in the state shown in FIG. 5, a mated optical path is formed connecting receptacle 10A side of device A and receptacle 10A' side of device B.

[0063] 6 shows a state in which a plug 30A provided as a first optical connector on one end of an optical cable 30Aa is mated with a receptacle 10A of a device A, but a plug 30A' provided as a second optical connector on the other end of the optical cable 30Aa is not mated with a receptacle 10A' of a device B. In this case, the plug 30A' side is in a detached state.

[0064] 6, light input to ferrule 12 from the transmission path inside the transmitting device (transmission path outside the transmitting optical cable) on the receptacle 10A side is collimated by lens (collimating lens) 17, passes through prism 13 and prism 33, and is focused by lens (condensing lens) 38 before being input to transmitting optical cable main body transmission path (transmission path inside the transmitting optical cable) 39 on the plug 30A side. Light output from this transmitting optical cable main body transmission path 39 is collimated by lens (collimating lens) 37', bent by prism 33', and incident on the reflecting surface of lower reflecting mirror 34'. The light reflected by reflecting mirror 34' is then incident on the reflecting surface of upper reflecting mirror 35'. Next, the light reflected by reflecting mirror 35' (reflected light) is bent by prism 33', condensed by lens (condensing lens) 38', and input to receiving-side optical cable main transmission path 36 on the plug 30A' side. Then, the light output from receiving-side optical cable main transmission path 36 is collimated by lens (collimating lens) 37, passes through prisms 33 and 13, is condensed by lens (condensing lens) 18, and input to receiving-side device internal transmission path (receiving-side optical cable external transmission path) 19 on the receptacle 10A side.

[0065] In this way, an optical path for the non-mated state is formed, and light transmitted from transmission path 16 within the transmitting device to ferrule 12 passes through prism 33' and reflecting mirrors 34' and 35' within plug 30A' and is returned to transmission path 19 within the receiving device as detection-use received light (disconnected state detection light, non-connected state detection light). This enables device A equipped with receptacle 10A to detect, as connection relationship information, that plug 30A' of optical cable 30Aa is in a disconnected state with receptacle 10A' of device B. In this case, light transmitted from transmission path 16 within the transmitting device to ferrule 12 is not output to the outside from the other end of housing 31' of plug 30A', thereby achieving eye safety.

[0066] 1-1-2. Structure in which the bending portion is a prism and the reflecting portion has one reflective surface" Fig. 7(a1) shows an example of the configuration of a receptacle 10B as an optical connector provided in a device, and Fig. 7(a2) shows an example of the configuration of a plug 30B as an optical connector provided in an optical cable 30Ba that is mated with this receptacle 10B. The plug 30B is a plug (first optical connector) provided at one end of the optical cable 30Ba, and a similar plug (second optical connector) is provided at the other end of the optical cable 30Ba. An optical cable main body 30B" is located between the plug 30B and the plug at the other end. In Figs. 7(a1) and (a2), parts corresponding to those in Figs. 1(a1) and (a2) are designated by the same reference numerals, and detailed descriptions thereof will be omitted as appropriate.

[0067] 7(a1), the receptacle 10B will be described. The receptacle 10B has a housing 11, a ferrule 12, a prism 13, and a reflecting mirror 20.

[0068] The ferrule 12 is integrally formed with a lens (collimating lens) 17 for collimating light (transmission light) transmitted from a transmission path within a transmitting device (transmission path outside a transmitting connector) 16 arranged at one end of the housing 11 and transmitting the light to the prism 13, and a lens (condensing lens) 18 for condensing light input from the prism 13 and transmitting the light to a transmission path within a receiving device (transmission path outside a receiving connector) 19 arranged at one end of the housing 11. In this case, the transmission path 16 within the transmitting device constitutes a part of the transmission path (first transmission path), and the transmission path 19 within the receiving device constitutes a part of the reception path (second transmission path), and the transmission path 16 within the transmitting device and the transmission path 19 within the receiving device constitute one intra-device transmission path set.

[0069] Although FIG. 7(a1) shows one transmission path 16 and one transmission path 19 within the receiving device, a plurality of transmission paths 16 and a plurality of transmission paths 19 within the receiving device may be provided. That is, a plurality of sets of transmission paths may be provided. For example, when a plurality of sets of transmission paths are provided, the sets of transmission paths may be arranged side by side in the depth direction of FIG. 7, i.e., in the left-right direction (y-axis direction) of FIG. 2 described above. In this case, each transmission path 16 within the receiving device is paired with one of the transmission paths 19 within the receiving device, and each pair of the transmission path 16 within the receiving device and the transmission path 19 within the receiving device constitutes an intra-device transmission path set. Each intra-device transmission path set is provided corresponding to each communication channel (transmission / reception channel).

[0070] The prism 13 forms a bending portion, and bends the light (transmitted light) input from the transmission path 16 inside the transmitting device, and emits the light into the space formed inside the housing 11. The bending angle of this bending portion is set to an angle at which the light (bent light) emitted into the space from the prism 13 is transmitted toward the reflecting mirror 20.

[0071] The reflecting surface of the reflecting mirror 20 constitutes a reflecting section. The reflecting mirror 20 is formed on the inside of the other end side of the housing 11. The reflection angle of this reflecting section is set to an angle at which light reflected by this reflecting section (reflected light) is transmitted toward the transmission path 19 in the receiving device via the prism 13. In this case, as shown in FIG. 7(b1), the reflecting surface of the reflecting mirror 20 is rotated by θy12 from the z-axis around the y-axis as the central axis in order to return the light from the prism 13 to a different position on the prism 13.

[0072] As shown in the figure, the operation of receptacle 10B will be described in a state in which plug 30B is not mated with receptacle 10B, i.e., in a detached state. In this case, light input from transmission path 16 in the transmitting device to ferrule 12 is collimated by lens (collimating lens) 17, then bent by prism 13 and incident on the reflective surface of reflecting mirror 20. Next, the light reflected by reflecting mirror 20 (reflected light) is bent by prism 13, condensed by lens (condensing lens) 18, and input to transmission path 19 in the receiving device.

[0073] In this way, an optical path is formed when the connector is not mated, and the light transmitted from transmission path 16 within the transmitting device to ferrule 12 is returned to transmission path 19 within the receiving device via prism 13 and reflecting mirror 20, thereby enabling the device equipped with receptacle 10B to detect that the connector is in a detached state. In addition, in this case, the light transmitted from transmission path 16 within the transmitting device to ferrule 12 is not output to the outside from the other end of housing 11, thereby achieving eye safety.

[0074] With reference to Fig. 7(a2), the plug 30B (first optical connector) provided in the optical cable 30Ba will be described. The optical cable 30Ba has an optical cable main body transmission line set consisting of two transmission lines, a transmitting side optical cable main body transmission line (transmission line outside the transmitting side connector) 39 and a receiving side optical cable main body transmission line (transmission line outside the receiving side connector) 36, as its optical cable main body transmission line. Plugs are provided on one end and the other end of this optical cable main body transmission line set, and Fig. 7(a2) shows the plug 30B on the one end side.

[0075] The plug 30B includes a housing 31, a ferrule 32, a prism 33, and a reflecting mirror 40.

[0076] The ferrule 32 is integrally formed with a lens (collimating lens) 37 for collimating light (receiving light) transmitted from a receiving-side optical cable main transmission line (transmission line outside the receiving connector) 36 arranged on the other end side of the housing 31 and inputting the light to the prism 33, and a lens (condensing lens) 38 for condensing the light input from the prism 33 and inputting it to a transmitting-side optical cable main transmission line (transmission line outside the transmitting connector) 39 arranged on the other end side of the housing 31. In this case, the transmitting-side optical cable main transmission line 39 constitutes a part of the transmitting-side transmission line (first transmission line), the receiving-side optical cable main transmission line 36 constitutes a part of the receiving-side transmission line (second transmission line), and the transmitting-side optical cable main transmission line 39 and the receiving-side optical cable main transmission line 36 constitute one optical cable main transmission line set.

[0077] Although FIG. 7( a2 ) shows one transmitting-side optical cable main transmission line 39 and one receiving-side optical cable main transmission line 36, a plurality of transmitting-side optical cable main transmission lines 39 and a plurality of receiving-side optical cable main transmission lines 36 may be provided. That is, a plurality of optical cable main transmission line sets may be provided. For example, when a plurality of optical cable main transmission line sets are provided, these optical cable transmission line sets may be arranged side by side in the depth direction of FIG. 7 , i.e., in the left-right direction (y-axis direction) of FIG. 2 described above. In this case, each transmitting-side optical cable main transmission line 39 is paired with one of the receiving-side optical cable main transmission lines 36, and each pair of the transmitting-side optical cable main transmission line 39 and the receiving-side optical cable main transmission line 36 constitutes an optical cable main transmission line set. Each optical cable main transmission line set is provided corresponding to each communication channel (transmitting and receiving channel).

[0078] The prism 33 constitutes a bending portion, and bends the light (received light) input from the receiving-side optical cable main transmission path 36 and emits it into the space formed within the housing 31. The bending angle of this bending portion is set to an angle at which the light (bent light) emitted into the space from the prism 33 is transmitted toward the reflecting mirror 40.

[0079] The reflecting surface of the reflecting mirror 40 constitutes a reflecting portion. The reflecting mirror 40 is formed on the inside of one end side of the housing 31. The reflection angle of this reflecting portion is set to an angle at which light reflected by this reflecting portion (reflected light) is transmitted toward the transmitting-side optical cable main transmission path 39 via the prism 33. In this case, as shown in FIG. 7(b2), the reflecting surface of the reflecting mirror 40 is rotated by θy32 from the z-axis around the y-axis as the central axis in order to return the light from the prism 33 to a different position on the prism 33.

[0080] As shown in the figure, the operation of plug 30B will be described in a state where plug 30B is not mated with receptacle 10B, i.e., in a detached state. In this case, light input from receiving-side optical cable main transmission line 36 to ferrule 32 is collimated by lens (collimating lens) 37, then bent by prism 33 and incident on the reflective surface of reflecting mirror 40. Next, light reflected by reflecting mirror 40 (reflected light) is bent by prism 33, condensed by lens (condensing lens) 38, and input to transmitting-side optical cable main transmission line 39.

[0081] In this way, an optical path is formed when the connector is not mated, and light transmitted from the receiving-side optical cable main body transmission path 36 to the ferrule 32 is returned to the transmitting-side optical cable main body transmission path 39 via the prism 33 and the reflecting mirror 40. In this case, the light transmitted from the receiving-side optical cable main body transmission path 36 to the ferrule 32 is not output to the outside from one end of the housing 31, thereby achieving eye safety.

[0082] Although detailed description will be omitted, the optical cable 30Ba has the above-mentioned plug 30B provided at one end as a first optical connector, and a plug 30B' configured similarly to the plug 30B is provided at the other end as a second optical connector. Furthermore, this optical cable 30Ba has a cross cable structure, in which the receiving-side optical cable main body transmission path 36 and the transmitting-side optical cable main body transmission path 39 cross midway through the optical cable main body 30B". These are the same as those of the above-mentioned optical cable 30Aa (see FIG. 3).

[0083] 8 shows a state in which a plug 30B is mated with a receptacle 10B. When the plug 30B is mated with the receptacle 10B, light input from the transmission path 16 in the receptacle 10B to the ferrule 12 is collimated by a lens (collimating lens) 17, passes through a prism 13 and a prism 33, is converged by a lens (converging lens) 38, and is input to a transmission path 39 in the optical cable main body of the plug 30B. When the plug 30B is mated with the receptacle 10B, light input from the reception path 36 in the optical cable main body of the plug 30B to the ferrule 32 is collimated by a lens (collimating lens) 37, passes through a prism 33 and a prism 13, is converged by a lens (converging lens) 18, and is input to a transmission path 19 in the receptacle 10B.

[0084] In this manner, when plug 30B is mated with receptacle 10B, a mated optical path is formed connecting receptacle 10B and plug 30B. Therefore, receiving-side device internal transmission path 19 functions as a reception / detection transmission path that serves both as a reception transmission path for light transmitted from device B and as a reception transmission path for received detection light (detachment state detection light, non-connection state detection light). Here, the optical path from lens (collimating lens) 17 of receptacle 10B to lens (condensing lens) 38 of plug 30B and the optical path from lens (collimating lens) 37 of plug 30B to lens (condensing lens) 18 of receptacle 10B can be realized by the design of prisms 13, 33.

[0085] Note that detailed description of the state in which receptacle 10B of device A is connected to receptacle 10B' of device B via optical cable 30Ba will be omitted here. This state is similar to the state in which receptacle 10A of device A is connected to receptacle 10A' of device B via optical cable 30Aa (see FIG. 5), and an optical path is formed during mating that connects receptacle 10B of device A with receptacle 10B' of device B.

[0086] Further, here, detailed explanation will be omitted regarding the state in which plug 30B provided as a first optical connector at one end of optical cable 30Ba is engaged with receptacle 10B of device A, while plug 30B' provided as a second optical connector at the other end of optical cable 30Ba is not engaged with receptacle 10B' of device B (plug 30B' side is in a detached state). This state is similar to the state in which the plug 30A provided as the first optical connector at one end of the optical cable 30Aa described above is engaged with the receptacle 10A of device A, but the plug 30A' provided as the second optical connector at the other end of the optical cable 30Aa is not engaged with the receptacle 10A' of device B (the plug 30A' side is in a detached state) (see Figure 6), and device A equipped with receptacle 10B can detect that the plug 30B' of the optical cable 30Ba is in a detached state with respect to the receptacle 10B' of device B.

[0087] 1-1-3. Structure in which the bending portion is a prism, the reflecting portion has one reflecting surface, and a detection-dedicated transmission path is added" Fig. 9(a1) shows an example of the configuration of a receptacle 10C as an optical connector provided in a device, and Fig. 9(a2) shows an example of the configuration of a plug 30C as an optical connector provided in an optical cable 30Ca that is fitted into this receptacle 10C. The plug 30C is a plug (first optical connector) provided at one end of the optical cable 30Ca, and a similar plug (second optical connector) is provided at the other end of the optical cable 30Ca. An optical cable main body 30C" is located between the plug 30C and the plug at the other end. In Figs. 9(a1) and (a2), parts corresponding to those in Figs. 1(a1) and (a2) are designated by the same reference numerals, and detailed descriptions thereof will be omitted as appropriate.

[0088] 9(a1), the receptacle 10C will be described. The receptacle 10C has a housing 11, a ferrule 21, a prism 13, and a reflecting mirror 22.

[0089] The ferrule 21 is integrally formed with a lens (collimating lens) 17 for collimating light (transmitted light) transmitted from a transmission path within the transmitting device (transmission path outside the transmitting connector) 16 arranged at one end of the housing 11 and inputting it to the prism 13, a lens (condensing lens) 18 for concentrating the light input from the prism 13 and inputting it to a first transmission path within the receiving device 19 arranged at one end of the housing 11 and which is a transmission path for communication, and a lens (condensing lens) 23 for concentrating the light input from the prism 13 side and inputting it to a second transmission path within the receiving device (transmission path outside the receiving connector) arranged at one end of the housing 11 and which is a transmission path dedicated to detection and not used for communicating actual data.

[0090] The detection-only intra-device transmission path 24 is disposed between the sending-side intra-device transmission path 16 and the first receiving-side intra-device transmission path 19. In this case, the sending-side intra-device transmission path 16 constitutes a part of the sending-side transmission path (first transmission path), and the first receiving-side intra-device transmission path 19 constitutes a part of the receiving-side transmission path (second transmission path). The sending-side intra-device transmission path 16, the first receiving-side intra-device transmission path 19, and the detection-only intra-device transmission path 24 constitute one intra-device transmission path set.

[0091] 9(a1) shows one transmission path 16 within the transmitting device, one first transmission path 19 within the receiving device, and one dedicated detection transmission path 24, but a plurality of transmission paths 16 within the transmitting device, a plurality of first transmission paths 19 within the receiving device, and a plurality of dedicated detection transmission paths 24 may be provided. That is, a plurality of sets of transmission paths within the device may be provided. For example, when a plurality of sets of transmission paths within the device are provided, the plurality of sets of transmission paths within the device may be arranged side by side in the depth direction of FIG. 9, i.e., in the left-right direction (y-axis direction) of FIG. 2 described above.

[0092] In this case, each transmission path 16 in the transmitting device is paired with any one of the first transmission path 19 in the receiving device and the dedicated detection transmission path 24 (corresponding to one communication channel), and the paired transmission path 16 in the transmitting device, the first transmission path 19 in the receiving device, and the dedicated detection transmission path 24 each constitute an intra-device transmission path set. Note that each intra-device transmission path set is provided corresponding to each communication channel (transmission and reception channel). Also, in FIG. 9(a1), the dedicated detection transmission path 24 is shown as being arranged between the transmission path 16 in the transmitting device and the first transmission path 19 in the receiving device, but it is not necessarily required that the dedicated detection transmission path 24 be arranged between the transmission path 16 in the transmitting device and the first transmission path 19 in the receiving device.

[0093] Here, the lenses 17, 18, and 23 may not be integral with the ferrule 21, but may be formed separately from the ferrule 21. Furthermore, the transmission path 16 in the sending device, the transmission path 19 in the first receiving device, and the transmission path 24 in the detection-dedicated device are configured as optical waveguides such as optical fibers, but these may also be spatial transmission paths.

[0094] The prism 13 forms a bending portion, and bends light (transmitted light) input from the transmission path 16 inside the transmitting device, and emits the light into the space formed inside the housing 11. The bending angle of this bending portion is set to an angle at which the light (bent light) emitted into the space from the prism 13 is transmitted toward the reflecting mirror 22.

[0095] The reflecting surface of the reflecting mirror 22 constitutes a reflecting section. The reflecting mirror 22 is formed on the inside of the other end side of the housing 11. The reflection angle of this reflecting section is set to an angle at which light reflected by this reflecting section (reflected light) is transmitted toward the transmission path 24 inside the detection-dedicated device via the prism 13. In this case, as shown in FIG. 9(b1), the reflecting surface of the reflecting mirror 22 is rotated by θy13 degrees from the z-axis around the y-axis as the central axis in order to return the light from the prism 13 to a different position on the prism 13.

[0096] As shown in the figure, the operation of receptacle 10C will be described in a state in which plug 30C is not mated with receptacle 10C, i.e., in a disconnected state. In this case, light input from transmission path 16 within the transmitting device to ferrule 21 is collimated by lens (collimating lens) 17, then bent by prism 13 and incident on the reflective surface of reflecting mirror 22. Next, light reflected by reflecting mirror 22 (reflected light) is bent by prism 13 and focused by lens (focusing lens) 23, and input to transmission path 24 within the detection-dedicated device as received light for detection, in this case, disconnected state detection light (disconnected state detection light).

[0097] In this way, an optical path is formed when the receptacle 10C is not mated, and the light transmitted from the transmission path 16 in the transmitting device to the ferrule 21 is returned to the transmission path 24 in the detection-only device via the prism 13 and the reflecting mirror 22, thereby enabling the device equipped with the receptacle 10C to detect that the receptacle 10C is in a detached state. In this case, the light transmitted from the transmission path 16 in the transmitting device to the ferrule 21 is not output to the outside from the other end of the housing 11, thereby achieving eye safety.

[0098] 9(a1), the detection-dedicated device internal transmission path 24 is positioned at a position offset from the midpoint between the sending-side device internal transmission path 16 and the first receiving-side device internal transmission path 19. The reason for this is to ensure eye safety when light is output from the detection-dedicated device internal transmission path 24.

[0099] When the detection-dedicated device transmission path 24 is located midway between the sending-side device transmission path 16 and the first receiving-side device transmission path 19, when light is output from the detection-dedicated device transmission path 24, the light travels directly to the right in the figure, enters the protruding portion of the prism 13, and branches into two beams in the upper and lower directions. In this case, because the angle of the protruding portion of the prism 13 is shallow, the light input to the prism 13 travels almost directly to the right in the figure and is output to the outside from the other end of the housing 11, thereby making eye safety unreliable. Incidentally, light may be output from the detection-dedicated device transmission path 24 if, for example, a break occurs in the detection-dedicated device transmission path 24, and the light input to the detection-dedicated device transmission path 24 (reflected light) is reflected at the break, and the reflected component is output from the detection-dedicated device transmission path 24.

[0100] The angle of the protruding portion of prism 13 is shallow because, when receptacle 10C and plug 30C are mated, light (reflected light) output from detection-dedicated optical cable main transmission path 44 on the plug 30C side is input to the protruding portion of prism 33 on the plug 30C side, branches into two in the upper and lower directions, and then passes through prism 33 and then prism 13 on the receptacle 10C side, and this branched light needs to be focused by lens (focusing lens) 23 and input to transmission path 24 within the detection-dedicated device.

[0101] If the detection-only device internal transmission path 24 is positioned at a position shifted from the midpoint between the sending device internal transmission path 16 and the first receiving device internal transmission path 19 as shown in Figure 9 (a1), when the receptacle 10C and plug 30C are mated, it is possible to prevent the light (reflected light) output from the detection-only optical cable main transmission path 44 on the plug 30C side from being input to the protruding part of the prism 33 on the plug 30C side, thereby preventing the light from branching into two in the upper and lower directions, and it is therefore possible to configure the angle of the protruding part of the prism 33 to be somewhat deep.

[0102] In this case, the light output from transmission path 24 within the detection-dedicated device is input to a position away from the protruding portion of prism 33, and travels at a fairly large angle diagonally to the horizontal direction to the right in the drawing without being branched into two (the optical path is schematically shown by dashed arrow P in FIG. 9(a1)). Therefore, by configuring the other end of housing 11 to have a sufficient length, the light output from transmission path 24 within the detection-dedicated device is not output directly to the outside, and eye safety is ensured.

[0103] In the configuration example of the receptacle 10C as an optical connector shown in Figure 9 (a1), the transmission path 24 within the detection-dedicated device is positioned at a position shifted from the midpoint between the transmission path 16 within the sending device and the first transmission path 19 within the receiving device. However, if there is no possibility of light being output from the transmission path 24 within the detection-dedicated device, or if there is a possibility of light being output from the transmission path 24 within the detection-dedicated device but the level is sufficiently small so that no eye-safety issues arise, the transmission path 24 within the detection-dedicated device may be configured to be positioned midpoint between the transmission path 16 within the sending device and the first transmission path 19 within the receiving device.

[0104] With reference to Fig. 9(a2), the plug 30C (first optical connector) provided in the optical cable 30Ca will be described. The optical cable 30Ca has an optical cable main body transmission line set consisting of two transmission lines, a transmitting side optical cable main body transmission line (transmission line outside the transmitting side connector) 39 and a receiving side optical cable main body transmission line (transmission line outside the receiving side connector) 36, as its optical cable main body transmission line. Plugs are provided on both ends of this optical cable main body transmission line set, and Fig. 9(a2) shows the plug 30C on the one end side.

[0105] The plug 30C includes a housing 31, a ferrule 41, a prism 33, and a reflecting mirror .

[0106] The ferrule 41 is integrally formed with a lens (collimating lens) 37 for collimating light (receiving light) transmitted from a receiving side optical cable main transmission path (transmission path outside the receiving side connector) 36 arranged on the other end side of the housing 31 and inputting it into the prism 33, a lens (condensing lens) 38 for concentrating the light input from the prism 33 and inputting it into a first transmitting side optical cable main transmission path 39 arranged on the other end side of the housing 31, and a lens (condensing lens) 43 for concentrating the light input from the prism 33 side and inputting it into a detection-only optical cable main transmission path (transmission path outside the transmitting side connector) 44, which is a second transmitting side optical cable main transmission path arranged on the other end side of the housing 31.

[0107] The detection-dedicated optical cable main transmission line 44 is disposed between the receiving-side optical cable main transmission line 36 and the first transmitting-side optical cable main transmission line 39. Although detailed description will be omitted here, similarly to the way the detection-dedicated intra-device transmission line 24 is disposed at a position offset from the midpoint between the transmitting-side device transmission line 16 and the first receiving-side device transmission line 19 on the receptacle 10C side, the detection-dedicated optical cable main transmission line 44 is disposed at a position offset from the midpoint between the receiving-side optical cable main transmission line 36 and the first transmitting-side optical cable main transmission line 39. In this case, the receiving-side optical cable main transmission line 36 constitutes a part of the receiving-side transmission line (second transmission line), and the first transmitting-side optical cable main transmission line 39 constitutes a part of the transmitting-side transmission line (first transmission line). Furthermore, the receiving-side optical cable main transmission line 36, the first transmitting-side optical cable main transmission line 39, and the detection-dedicated optical cable main transmission line 44 constitute one optical cable main transmission line set.

[0108] 9(a2) shows one receiving-side optical cable main transmission line 36, one first transmitting-side optical cable main transmission line 39, and one detection-dedicated optical cable main transmission line 44, but a plurality of receiving-side optical cable main transmission lines 36, a plurality of first transmitting-side optical cable main transmission lines 39, and a plurality of detection-dedicated optical cable main transmission lines 44 may be provided. That is, a plurality of optical cable main transmission line sets may be provided. For example, when a plurality of optical cable main transmission line sets are provided, the plurality of optical cable main transmission line sets may be arranged side by side in the depth direction of FIG. 9, i.e., in the left-right direction (y-axis direction) of FIG. 2 described above.

[0109] In this case, each reception-side optical cable main transmission line 36 is paired with any one of the first transmission-side optical cable main transmission lines 39 and the detection-dedicated optical cable main transmission line 44, and the paired reception-side optical cable main transmission line 36, first transmission-side optical cable main transmission line 39, and detection-dedicated optical cable main transmission line 44 constitute an optical cable main transmission line set. Note that each optical cable main transmission line set is provided corresponding to each communication channel (transmission and reception channel). Also, in Fig. 9(a2), the detection-dedicated optical cable main transmission line 44 is illustrated as being disposed between the reception-side optical cable main transmission line 36 and the first transmission-side optical cable main transmission line 39, but it is not necessarily required that the detection-dedicated optical cable main transmission line 44 be disposed between the reception-side optical cable main transmission line 36 and the first transmission-side optical cable main transmission line 39.

[0110] Here, the lenses 37, 38, and 43 may not be integral with the ferrule 41 but may be formed separately from the ferrule 41. Furthermore, the receiving-side optical cable main transmission line 36, the first transmitting-side optical cable main transmission line 39, and the detection-dedicated optical cable main transmission line 44 are configured with optical waveguides such as optical fibers.

[0111] The prism 33 constitutes a bending portion, and bends the light (received light) input from the receiving-side optical cable main transmission path 36 and emits it into the space formed within the housing 31. The bending angle of this bending portion is set to an angle at which the light (bent light) emitted into the space from the prism 33 is transmitted toward the reflecting mirror 42.

[0112] The reflecting surface of the reflecting mirror 42 constitutes a reflecting portion. The reflecting mirror 42 is formed on the inside of one end side of the housing 31. The reflection angle of this reflecting portion is set to an angle at which light reflected by this reflecting portion (reflected light) is transmitted toward the detection-dedicated optical cable main transmission path 44 via the prism 33. In this case, as shown in FIG. 9(b2), the reflecting surface of the reflecting mirror 42 is rotated by θy33 degrees from the z-axis around the y-axis as its central axis in order to return the light from the prism 33 to a different position on the prism 33.

[0113] As shown in the figure, the operation of plug 30C will be described in a state in which plug 30C is not mated with receptacle 10C, i.e., in a disconnected state. In this case, light input from receiving-side optical cable main transmission path 36 to ferrule 41 is collimated by lens (collimating lens) 37, then bent by prism 33 and incident on the reflective surface of reflecting mirror 42. Next, light reflected by reflecting mirror 42 (reflected light) is bent by prism 33 and focused by lens (focusing lens) 43, and input to detection-dedicated optical cable main transmission path 44 as received light for detection, in this case, disconnected state detection light (disconnected state detection light).

[0114] In this way, an optical path is formed when the connector is not mated, and light transmitted from the receiving-side optical cable main transmission path 36 to the ferrule 41 is returned to the detection-only optical cable main transmission path 44 via the prism 33 and the reflecting mirror 42. In this case, the light transmitted from the receiving-side optical cable main transmission path 36 to the ferrule 41 is not output to the outside from one end of the housing 31, thereby achieving eye safety.

[0115] FIG. 10 shows the overall configuration of an optical cable 30Ca, in which the above-mentioned plug 30C is provided at one end as a first optical connector, and a plug 30C' configured similarly to the plug 30C is provided at the other end as a second optical connector. An optical cable main body 30C" is present between the plugs 30C and 30C', and this optical cable main body 30C" includes the above-mentioned optical cable main body transmission paths (receiving-side optical cable main body transmission path 36, transmitting-side optical cable main body transmission path 39). Since the plug 30C' is configured similarly to the plug 30C, detailed description thereof will be omitted. Each part of the plug 30C' is designated by a symbol obtained by adding a prime symbol to the symbol designated to each part of the plug 30C, so that the correspondence between each part of the plug 30C' and each part of the plug 30C can be clarified.

[0116] Moreover, this optical cable 30Ca has a cross cable structure, in which the receiving-side optical cable main body transmission path 36 and the transmitting-side optical cable main body transmission path 39 cross in the middle of the optical cable main body 30C". Therefore, in this optical cable 30Ca, light output from the lens (condensing lens) 38 of the plug 30C and input to the transmitting-side optical cable main body transmission path 39 is output from this transmitting-side optical cable main body transmission path 39 and input to the lens (collimating lens) 37' of the plug 30C'. Also, this optical cable 30Ca In the optical cable 30Ca, light output from the lens (condensing lens) 38' of the plug 30C' and input to the reception-side optical cable main transmission path 36 is output from this reception-side optical cable main transmission path 36 and input to the lens (collimating lens) 37 of the plug 30C. Also, in the optical cable 30Ca, light output from the lens (condensing lens) 43' of the plug 30C' and input to the detection-dedicated optical cable main transmission path 44 is output from this detection-dedicated optical cable main transmission path 44 and input to the lens (collimating lens) 43 of the plug 30C.

[0117] 11 shows a state in which a plug 30C is mated with a receptacle 10C. When the plug 30C is mated with the receptacle 10C, light input from the transmission path 16 in the receptacle 10C to the ferrule 21 is collimated by a lens (collimating lens) 17, passes through prisms 13 and 33, is converged by a lens (converging lens) 38, and is input to a first transmission-side optical cable main transmission path 39 in the plug 30C. When the plug 30C is mated with the receptacle 10C, light input from the reception-side optical cable main transmission path 36 in the plug 30C to the ferrule 41 is collimated by a lens (collimating lens) 37, passes through prisms 33 and 13, is converged by a lens (converging lens) 18, and is input to a reception-side device transmission path 19 in the receptacle 10C. Furthermore, when plug 30C is fitted into receptacle 10C, light input from detection-only optical cable main transmission path 44 on the plug 30C side to ferrule 41 is collimated by lens (collimating lens) 43, passes through prism 33 and prism 13, is focused by lens (focusing lens) 23, and is input to detection-only device internal transmission path 24 on the receptacle 10C side.

[0118] In this manner, when plug 30C is mated with receptacle 10C, a mated optical path is formed connecting receptacle 10C and plug 30C. The optical path from lens (collimating lens) 17 of receptacle 10C to lens (collimating lens) 38 of plug 30C, the optical path from lens (collimating lens) 37 of plug 30C to lens (collimating lens) 18 of receptacle 10C, and the optical path from lens (collimating lens) 43 of plug 30C to lens (collimating lens) 23 of receptacle 10C can be realized by the design of prisms 13 and 33.

[0119] 12 shows a state in which a receptacle 10C of device A is connected to a receptacle 10C' of device B via an optical cable 30Ca (see FIG. 10). In this case, a plug 30C provided as a first optical connector on one end of the optical cable 30Ca is mated with the receptacle 10C of device A, and a plug 30C' provided as a second optical connector on the other end of the optical cable 30Ca is mated with the receptacle 10C' of device B. Note that the receptacle 10C' has the same configuration as the receptacle 10C, and therefore a detailed description thereof will be omitted. Each part of the receptacle 10C' is designated by a symbol obtained by adding a prime symbol to the symbol designated to each part of the receptacle 10C, so that the correspondence between each part of the receptacle 10C' and each part of the receptacle 10C can be clearly seen.

[0120] 12, light input to ferrule 12 from transmission path 16 in the transmitting device on the receptacle 10A side is collimated by lens (collimating lens) 17, passes through prisms 13 and 33, is focused by lens (condensing lens) 38, and is input to transmission path 39 in the transmitting optical cable main body on the plug 30C side. Then, light output from transmission path 39 in the transmitting optical cable main body is collimated by lens (collimating lens) 37' on the plug 30C' side, passes through prisms 33' and 13', is focused by lens (condensing lens) 18', and is input to transmission path 19' in the transmitting device on the receptacle 10C' side.

[0121] 12, light input from receiving-side device internal transmission path 16' on the receptacle 10C' side to ferrule 12' is collimated by lens (collimating lens) 17', passes through prism 13' and prism 33', is focused by lens (condensing lens) 38', and is input to receiving-side optical cable main body transmission path 36 on the plug 30C' side. Light output from receiving-side optical cable main body transmission path 36 is collimated by lens (collimating lens) 37 on the plug 30C side, passes through prism 33 and prism 13, is focused by lens (condensing lens) 18, and is input to receiving-side device internal transmission path 19 on the receptacle 10A side. In this way, in the state shown in FIG. 12, a mated optical path is formed connecting receptacle 10C of device A and receptacle 10C' of device B.

[0122] 13 shows a state in which plug 30C provided as a first optical connector on one end of optical cable 30Ca is mated with receptacle 10C of device A, but plug 30C' provided as a second optical connector on the other end of optical cable 30Ca is not mated with receptacle 10C' of device B. In this case, plug 30C' is in a detached state.

[0123] 13 , light input to the ferrule 12 from the transmission path 16 in the receptacle 10C is collimated by the lens (collimating lens) 17, passes through the prisms 13 and 33, and is focused by the lens (focusing lens) 38 before being input to the transmission-side optical cable main transmission path 39 in the plug 30C. The light output from the transmission-side optical cable main transmission path 39 is collimated by the lens (collimating lens) 37' in the plug 30C', is bent by the prism 33', and is incident on the reflecting surface of the reflecting mirror 42'. The light reflected by the reflecting mirror 42' (reflected light) is then bent by the prism 33', focused by the lens (focusing lens) 43', and input to the detection-dedicated optical cable main transmission path 44. The light output from the detection-only optical cable main transmission path 44 is collimated by the lens (collimating lens) 43 on the plug 30C side, passes through the prism 33 and the prism 13, is focused by the lens (focusing lens) 23, and is input to the detection-only device internal transmission path 24 on the receptacle 10C side.

[0124] In this way, an optical path for when the connector is not mated is formed, and light transmitted from transmission path 16 within the transmitting device to ferrule 12 passes through prism 33' and reflecting mirror 42' within plug 30C' and is returned to transmission path 24 within the detection-dedicated device as received light for detection (disconnected state detection light, non-connected state detection light), thereby enabling device A equipped with receptacle 10C to detect that plug 30C' of optical cable 30Ca is in a disconnected state with respect to receptacle 10C' of device B. In addition, in this case, light transmitted from transmission path 16 within the transmitting device to ferrule 12 is not output to the outside from the other end of housing 31' of plug 30C', thereby achieving eye safety.

[0125] While the receptacle 10C shown in FIG. 9(a1) illustrates an example in which the bending portion is configured with a prism 13 and the reflecting portion is configured with the reflecting surface of a single reflecting mirror 22, this is not limiting. For example, the bending portion may be configured with the reflecting surface of a reflecting mirror, or the reflecting portion may be configured with the reflecting surfaces of two reflecting mirrors. In this case, for example, the bending portion may be configured with a prism and the reflecting portion may be configured with the reflecting surfaces of two reflecting mirrors. Furthermore, in this case, for example, the bending portion may be configured with the reflecting surface of a reflecting mirror, and the reflecting portion may be configured with the reflecting surface of one reflecting mirror or two reflecting mirrors. In this case, a reflecting mirror is required to guide light to the transmission path 24 within the detection-dedicated device when not mated, without interfering with the optical path when mated. This also applies to the plug 30C shown in FIG. 9(a2).

[0126] 1-1-4. Structure in which the bending portion is a prism, the reflecting portion has two reflective surfaces, and a detection-dedicated transmission path is added" Fig. 14(a1) shows an example of the configuration of a receptacle 10D as an optical connector provided in a device, and Fig. 14(a2) shows an example of the configuration of a plug 30D as an optical connector provided in an optical cable 30Da that is mated with this receptacle 10D. The plug 30D is a plug (first optical connector) provided at one end of the optical cable 30Da, and a similar plug (second optical connector) is provided at the other end of the optical cable 30Da. An optical cable main body 30D" is located between the plug 30D and the plug at the other end. In Figs. 14(a1) and (a2), parts corresponding to those in Figs. 9(a1) and (a2) are designated by the same reference numerals, and detailed descriptions thereof will be omitted as appropriate.

[0127] 14(a1), the receptacle 10D will be described. The receptacle 10D has a housing 11, a ferrule 21, a prism 13, a reflecting mirror 27, and a reflecting mirror .

[0128] The ferrule 21 is integrally formed with a lens (collimating lens) 17 for collimating light (transmitted light) transmitted from a transmission path within the transmitting device (transmission path outside the transmitting connector) 16 located at one end of the housing 11 and inputting it to the prism 13, a lens (condensing lens) 18 for concentrating the light input from the prism 13 and inputting it to a first transmission path within the receiving device 19 located at one end of the housing 11 and which is a transmission path for communication, and a lens (condensing lens) 23 for concentrating the light input from the prism 13 side and inputting it to a transmission path within the detection-only device 24 located at one end of the housing 11 and which is a second transmission path within the receiving device (transmission path outside the receiving connector) and which is a transmission path dedicated to detection.

[0129] The detection-only intra-device transmission path 24 is disposed between the transmission path 16 within the sending device and the first transmission path 19 within the receiving device. Although detailed description will be omitted here, similar to the configuration example of the receptacle 10C in FIG. 9( a1 ) described above, the detection-only intra-device transmission path 24 is disposed at a position shifted from the midpoint between the transmission path 16 within the sending device and the first transmission path 19 within the receiving device. In this case, the transmission path 16 within the sending device constitutes a part of the sending-side transmission path (first transmission path), and the first transmission path 19 within the receiving device constitutes a part of the receiving-side transmission path (second transmission path). The transmission path 16 within the sending device, the first transmission path 19 within the receiving device, and the detection-only intra-device transmission path 24 constitute one intra-device transmission path set.

[0130] 14(a1) shows one transmission path 16 within the transmitting device, one first transmission path 19 within the receiving device, and one dedicated detection transmission path 24, but a plurality of transmission paths 16 within the transmitting device, a plurality of first transmission paths 19 within the receiving device, and a plurality of dedicated detection transmission paths 24 may be provided. That is, a plurality of sets of transmission paths within the device may be provided. For example, when a plurality of sets of transmission paths within the device are provided, the plurality of sets of transmission paths within the device may be arranged side by side in the depth direction of FIG. 14, i.e., in the left-right direction (y-axis direction) of FIG. 2 described above.

[0131] In this case, each transmission path 16 in the transmitting device is paired with any one of the first transmission paths 19 in the receiving device and the dedicated detection transmission path 24 (corresponding to one communication channel), and each pair of the transmission path 16 in the transmitting device, the first transmission path 19 in the receiving device, and the dedicated detection transmission path 24 constitutes an intra-device transmission path set. Note that each intra-device transmission path set is provided corresponding to each communication channel (transmission and reception channel). Also, in FIG. 14(a1), the detection-only intra-device transmission path 24 is shown as being arranged between the transmission path 16 in the transmitting device and the first transmission path 19 in the receiving device, but it is not necessarily required that the detection-only intra-device transmission path 24 be arranged between the transmission path 16 in the transmitting device and the first transmission path 19 in the receiving device.

[0132] Here, the lenses 17, 18, and 23 may not be integral with the ferrule 21, but may be formed separately from the ferrule 21. Furthermore, the transmission path 16 in the sending device, the transmission path 19 in the first receiving device, and the transmission path 24 in the detection-dedicated device are configured as optical waveguides such as optical fibers, but these may also be spatial transmission paths.

[0133] The prism 13 forms a bending portion, and bends the light (transmitted light) input from the transmission path 16 inside the transmitting device and emits it into the space formed inside the housing 11. The bending angle of this bending portion is set to an angle at which the light (bent light) emitted into the space from the prism 13 is transmitted toward the reflecting mirror 27.

[0134] The reflecting surfaces of the reflecting mirrors 27 and 28 constitute a reflecting section. The reflecting mirrors 27 and 28 are formed at positions facing each other inside the other end side of the housing 11. The reflection angle of the reflecting section is set to an angle at which light reflected by the reflecting section (reflected light) is transmitted toward the transmission path 24 inside the detection-dedicated device via the prism 13.

[0135] In this case, as shown in FIG. 14(b1), the reflective surface of the reflective mirror 27 is rotated θy14 degrees from the z-axis around the y-axis (θy14 = 0 in the illustrated example) to reflect light from the prism 13 upward in the figure, and the reflective surface of the reflective mirror 28 is rotated −θy15 degrees from the z-axis around the y-axis to reflect light from below toward the prism 13, as shown in FIG. 14(b1). Note that in the illustrated example, the reflective surfaces of the reflective mirrors 27 and 28 are flat, but any shape may be used as long as it does not impair their function as reflectors. For example, the reflective surface of the reflective mirror 27 may be concave and the reflective surface of the reflective mirror 28 may be convex, or vice versa.

[0136] As shown in the figure, the operation of receptacle 10D will be described in a state in which plug 30D is not mated with receptacle 10D, i.e., in a disconnected state. In this case, light input from transmission path 16 within the transmitting device to ferrule 21 is collimated by lens (collimating lens) 17, then bent by prism 13 and incident on the reflective surface of lower reflecting mirror 27. Next, the light reflected by reflecting mirror 27 is incident on the reflective surface of upper reflecting mirror 28. Next, the light reflected by reflecting mirror 28 (reflected light) is bent by prism 13 and focused by lens (focusing lens) 23, and input to detection-dedicated internal transmission path 24 as received light for detection, in this case, disconnected state detection light (disconnected state detection light).

[0137] In this way, an optical path for the disconnected state is formed, and the transmitted light transmitted from transmission path 16 within the transmitting device to ferrule 21 is returned to transmission path 24 within the detection-dedicated device as received light for detection (disconnected state detection light, non-connected state detection light) via prism 13 and reflecting mirrors 27, 28, thereby enabling the device equipped with receptacle 10D to detect that it is in a disconnected state. In addition, in this case, the light transmitted from transmission path 16 within the transmitting device to ferrule 21 is not output to the outside from the other end of housing 11, thereby achieving eye safety.

[0138] Referring to Fig. 14(a2), a plug 30D (first optical connector) provided in the optical cable 30Da will be described. The optical cable 30Da has an optical cable main body transmission line set consisting of two transmission lines, a transmitting side optical cable main body transmission line (transmission line outside the transmitting side connector) 39 and a receiving side optical cable main body transmission line (transmission line outside the receiving side connector) 36, as its optical cable main body transmission line. Plugs are provided on one end and the other end of this optical cable main body transmission line set, and Fig. 14(a2) shows the plug 30D on the one end side.

[0139] The plug 30D includes a housing 31, a ferrule 41, a prism 33, a reflecting mirror 47, and a reflecting mirror .

[0140] The ferrule 41 is integrally formed with a lens (collimating lens) 37 for collimating light (receiving light) transmitted from a receiving side optical cable main transmission path (transmission path outside the receiving side connector) 36 arranged on the other end side of the housing 31 and inputting it into the prism 33, a lens (condensing lens) 38 for concentrating the light input from the prism 33 and inputting it into a first transmitting side optical cable main transmission path 39 arranged on the other end side of the housing 31, and a lens (condensing lens) 43 for concentrating the light input from the prism 33 side and inputting it into a detection-only optical cable main transmission path (transmission path outside the transmitting side connector) 44, which is a second transmitting side optical cable main transmission path arranged on the other end side of the housing 31.

[0141] The detection-dedicated optical cable main transmission line 44 is disposed between the receiving-side optical cable main transmission line 36 and the first transmitting-side optical cable main transmission line 39. Although detailed description will be omitted here, similarly to the way in which the detection-dedicated intra-device transmission line 24 is disposed at a position offset from the midpoint between the transmitting-side device transmission line 16 and the first receiving-side device transmission line 19 on the receptacle 10D side, the detection-dedicated optical cable main transmission line 44 is disposed at a position offset from the midpoint between the receiving-side optical cable main transmission line 36 and the first transmitting-side optical cable main transmission line 39. In this case, the receiving-side optical cable main transmission line 36 constitutes a part of the receiving-side transmission line (second transmission line), and the first transmitting-side optical cable main transmission line 39 constitutes a part of the transmitting-side transmission line (first transmission line). Furthermore, the receiving-side optical cable main transmission line 36, the first transmitting-side optical cable main transmission line 39, and the detection-dedicated optical cable main transmission line 44 constitute one optical cable main transmission line set.

[0142] 14(a2) shows one receiving-side optical cable main transmission line 36, one first transmitting-side optical cable main transmission line 39, and one detection-dedicated optical cable main transmission line 44, but a plurality of receiving-side optical cable main transmission lines 36, a plurality of first transmitting-side optical cable main transmission lines 39, and a plurality of detection-dedicated optical cable main transmission lines 44 may be provided. That is, a plurality of optical cable main transmission line sets may be provided. For example, when a plurality of optical cable main transmission line sets are provided, the plurality of optical cable main transmission line sets may be arranged side by side in the depth direction of FIG. 14, i.e., in the left-right direction (y-axis direction) of FIG. 2 described above.

[0143] In this case, each reception-side optical cable main transmission line 36 is paired with any one of the first transmission-side optical cable main transmission lines 39 and the detection-dedicated optical cable main transmission line 44, and the paired reception-side optical cable main transmission line 36, first transmission-side optical cable main transmission line 39, and detection-dedicated optical cable main transmission line 44 constitute an optical cable main transmission line set. Note that each optical cable main transmission line set is provided corresponding to each communication channel (transmission and reception channel). Also, in Fig. 14(a2), the detection-dedicated optical cable main transmission line 44 is illustrated as being disposed between the reception-side optical cable main transmission line 36 and the first transmission-side optical cable main transmission line 39, but it is not necessarily required that the detection-dedicated optical cable main transmission line 44 be disposed between the reception-side optical cable main transmission line 36 and the first transmission-side optical cable main transmission line 39.

[0144] Here, the lenses 37, 38, and 43 may not be integral with the ferrule 41 but may be formed separately from the ferrule 41. Furthermore, the receiving-side optical cable main transmission line 36, the first transmitting-side optical cable main transmission line 39, and the detection-dedicated optical cable main transmission line 44 are configured with optical waveguides such as optical fibers.

[0145] The prism 33 constitutes a bending portion, and bends the light (received light) input from the receiving-side optical cable main transmission path 36 and emits it into the space formed within the housing 31. The bending angle of this bending portion is set to an angle at which the light (bent light) emitted into the space from this prism 33 is transmitted toward the reflecting mirror 47.

[0146] The reflecting surfaces of the reflecting mirrors 47 and 48 constitute a reflecting section. The reflecting mirrors 47 and 48 are formed at positions facing each other inside one end of the housing 31. The reflection angle of the reflecting section is set to an angle at which light reflected by the reflecting section (reflected light) is transmitted via the prism 33 toward the transmission path 44 inside the dedicated detection device.

[0147] In this case, as shown in FIG. 14(b2), the reflective surface of the reflective mirror 47 is rotated by θy34 degrees from the z-axis around the y-axis as its central axis to reflect light from the prism 33 upward in the figure, and the reflective surface of the reflective mirror 48 is rotated by -θy35 degrees from the z-axis around the y-axis as its central axis to reflect light from below toward the prism 33, as shown in FIG. 14(b2). Note that in the illustrated example, the reflective surfaces of the reflective mirrors 47 and 48 are flat, but any shape may be used as long as it does not impair their function as reflectors. For example, the reflective surface of the reflective mirror 47 may be concave and the reflective surface of the reflective mirror 48 may be convex, or vice versa.

[0148] As shown in the figure, the operation of plug 30D will be described in a state where plug 30D is not mated with receptacle 10D, i.e., in a detached state. In this case, light input from reception-side optical cable main transmission line 36 to ferrule 41 is collimated by lens (collimating lens) 37, then bent by prism 33 and incident on the reflecting surface of reflecting mirror 47. Next, the light reflected by reflecting mirror 47 is incident on the reflecting surface of upper reflecting mirror 48. Next, the light reflected by reflecting mirror 48 (reflected light) is bent by prism 33, condensed by lens (condensing lens) 43, and input to detection-dedicated optical cable main transmission line 44.

[0149] In this way, a non-mated optical path is formed, and the light transmitted from the receiving-side optical cable main transmission path 36 to the ferrule 41 is returned to the detection-dedicated optical cable main transmission path 44 as received light for detection (disconnection state detection light, non-connection state detection light) via the prism 33 and the reflecting mirrors 47, 48. In this case, the light transmitted from the receiving-side optical cable main transmission path 36 to the ferrule 41 is not output to the outside from one end side of the housing 31, thereby realizing eye safety.

[0150] Although detailed description will be omitted, an optical cable 30Da has the above-mentioned plug 30D provided at one end as a first optical connector, and a plug 30D' configured similarly to the plug 30D provided at the other end as a second optical connector. Furthermore, this optical cable 30Da has a cross cable structure, in which the receiving-side optical cable main body transmission path 36 and the transmitting-side optical cable main body transmission path 39 cross midway through the optical cable main body 30D". These are the same as those of the above-mentioned optical cable 30Ca (see FIG. 10).

[0151] 15 shows a state in which a plug 30D is mated with a receptacle 10D. With the plug 30D mated with the receptacle 10D, light input from the transmission path 16 in the receptacle 10D to the ferrule 21 is collimated by a lens (collimating lens) 17, passes through prisms 13 and 33, is converged by a lens (converging lens) 38, and is input to a first transmission-side optical cable main transmission path 39 in the plug 30D. With the plug 30D mated with the receptacle 10D, light input from the reception-side optical cable main transmission path 36 in the plug 30D to the ferrule 41 is collimated by a lens (collimating lens) 37, passes through prisms 33 and 13, is converged by a lens (converging lens) 18, and is input to a reception-side device transmission path 19 in the receptacle 10D. Furthermore, when plug 30D is fitted into receptacle 10D, light input from detection-only optical cable main transmission path 44 on the plug 30D side to ferrule 41 is collimated by lens (collimating lens) 43, passes through prism 33 and prism 13, is focused by lens (focusing lens) 23, and is input to detection-only device internal transmission path 24 on the receptacle 10D side.

[0152] In this manner, when plug 30D is mated with receptacle 10D, a mated optical path is formed connecting receptacle 10D and plug 30D. The optical path from lens (collimating lens) 17 of receptacle 10D to lens (collimating lens) 38 of plug 30D, the optical path from lens (collimating lens) 37 of plug 30D to lens (collimating lens) 18 of receptacle 10D, and the optical path from lens (collimating lens) 43 of plug 30D to lens (collimating lens) 23 of receptacle 10D can be realized by the design of prisms 13 and 33.

[0153] Note that detailed description of the state in which receptacle 10D of device A is connected to receptacle 10D' of device B via optical cable 30Da will be omitted here. This state is similar to the state in which receptacle 10C of device A is connected to receptacle 10C' of device B via optical cable 30Ca (see FIG. 12), and an optical path during mating is formed connecting receptacle 10D of device A and receptacle 10D' of device B.

[0154] Further, here, detailed explanation will be omitted regarding the state in which plug 30D provided as a first optical connector at one end of optical cable 30Da is engaged with receptacle 10B of device A, while plug 30D' provided as a second optical connector at the other end of optical cable 30Da is not engaged with receptacle 10B' of device B (plug 30D' side is in a detached state). This state is the same as the state in which the plug 30C provided as the first optical connector at one end of the optical cable 30Ca described above is engaged with the receptacle 10C of the device A, but the plug 30C' provided as the second optical connector at the other end of the optical cable 30Ca is not engaged with the receptacle 10C' of the device B (the plug 30C' side is in a detached state) (see Figure 13), and the device A equipped with the receptacle 10D can detect that the plug 30D' of the optical cable 30Da is in a detached state with respect to the receptacle 10D' of the device B.

[0155] 1-1-5. Structure in which the bent portion is two reflective surfaces and the reflective portion has two reflective surfaces" Fig. 16(a1) shows an example of the configuration of a receptacle 10E as an optical connector provided in a device, and Fig. 16(a2) shows an example of the configuration of a plug 30E as an optical connector provided in an optical cable 30Ea that is mated with this receptacle 10E. The plug 30E is a plug (first optical connector) provided on one end of the optical cable 30Ea, and a similar plug (second optical connector) is provided on the other end of the optical cable 30Ea. An optical cable main body 30E" is located between the plug 30E and the plug on the other end. In Figs. 16(a1) and (a2), parts corresponding to those in Figs. 1(a1) and (a2) are designated by the same reference numerals, and detailed descriptions thereof will be omitted as appropriate.

[0156] 16(a1), the receptacle 10E will be described. The receptacle 10E has a housing 11, a ferrule 12, a reflecting mirror 25, a reflecting mirror 26, a reflecting mirror 14, and a reflecting mirror 15.

[0157] The ferrule 12 is integrally formed with a lens (collimator lens) 17 for inputting light (transmission light) transmitted from a transmission path within a transmitting device (transmission path outside a transmitting connector) 16 arranged at one end of the housing 11 to a reflection mirror 25, and a lens (condenser lens) 18 for condensing the light input from the reflection mirror 26 and inputting it to a transmission path within a receiving device 19 (transmission path outside a receiving connector) arranged at one end of the housing 11. In this case, the transmission path within the transmitting device 16 constitutes a part of the transmission path (first transmission path), and the transmission path within the receiving device 19 constitutes a part of the reception path (second transmission path), and the transmission path within the transmitting device 16 and the transmission path within the receiving device 19 constitute one intra-device transmission path set.

[0158] Although FIG. 16(a1) shows one transmission path 16 and one transmission path 19 in the receiving device, a plurality of transmission paths 16 and a plurality of transmission paths 19 in the receiving device may be provided. That is, a plurality of sets of transmission paths may be provided. For example, when a plurality of sets of transmission paths are provided, the plurality of sets of transmission paths may be arranged side by side in the depth direction of FIG. 16, i.e., in the left-right direction (y-axis direction) in FIG. 2 described above. In this case, each transmission path 16 in the receiving device is paired with one of the transmission paths 19 in the receiving device, and each pair of the transmission path 16 in the receiving device and the transmission path 19 in the receiving device constitutes an intra-device transmission path set. Each intra-device transmission path set is provided corresponding to each communication channel (transmission / reception channel).

[0159] The reflective surfaces of the reflecting mirror 25 and the reflecting mirror 26 form a bending portion. The reflective surface of the reflecting mirror 25 bends light (transmitted light) input from the transmission path 16 in the transmitting device and emits it into the space formed within the housing 11. The bending angle is set to an angle at which the light (bent light) output from the reflecting mirror 25 into the space is transmitted toward the reflecting mirror 14. The reflective surface of the reflecting mirror 26 bends light (reflected light) input from the reflecting mirror 15 and emits it toward the transmission path 19 in the receiving device. In the illustrated example, the reflective surfaces of the reflecting mirror 25 and the reflecting mirror 26 are flat, but any shape may be used as long as it does not impede their function as bending portions. For example, the reflective surface of the reflecting mirror 25 may be convex and the reflective surface of the reflecting mirror 26 may be concave, or vice versa.

[0160] The reflecting surfaces of the reflecting mirrors 14 and 15 constitute a reflecting section. The reflecting mirrors 14 and 15 are formed at positions facing each other inside the other end side of the housing 11. The reflection angle of the reflecting section is set to an angle at which light reflected by the reflecting section (reflected light) is transmitted toward the transmission path 19 in the receiving device via the reflecting mirror 26.

[0161] In this case, as shown in Figure 16 (b1), the reflective surface of reflective mirror 14 is rotated by θy11 degrees from the z-axis around the y-axis as the central axis in order to reflect light from reflective mirror 25 upward in the figure, and the reflective surface of reflective mirror 15 is rotated by -θy11 degrees from the z-axis around the y-axis as the central axis in order to reflect light from below in the figure toward reflective mirror 26, as shown in Figure 16 (b1).

[0162] As shown in the figure, the operation of receptacle 10E will be described in a state in which plug 30E is not mated with receptacle 10E, i.e., in a disconnected state. In this case, light input from transmission path 16 within the transmitting device to ferrule 12 is collimated by lens (collimating lens) 17, then bent by reflecting mirror 25 and incident on the reflective surface of lower reflecting mirror 14. Next, the light reflected by reflecting mirror 14 is incident on the reflective surface of upper reflecting mirror 15. Next, the light reflected by reflecting mirror 15 (reflected light) is bent by reflecting mirror 26 and focused by lens (focusing lens) 18, and input to transmission path 19 within the receiving device as received light for detection, in this case, disconnected state detection light (disconnected state detection light).

[0163] In this way, an optical path for when the connector is not mated is formed, and light transmitted from transmission path 16 within the transmitting device to ferrule 12 passes through reflecting mirrors 25, 26 that form the bending portion and reflecting mirrors 14, 15 that form the reflecting portion, and is returned to transmission path 19 within the receiving device as received light for detection (disconnection state detection light, non-connection state detection light), thereby enabling a device equipped with receptacle 10E to detect that plug 30E is disconnected from receptacle 10E, in other words, that an optical cable equipped with connector 30E is disconnected from a device equipped with receptacle 10E. Furthermore, in this case, light transmitted from transmission path 16 within the transmitting device to ferrule 12 is not output to the outside from the other end of housing 11, thereby achieving eye safety.

[0164] With reference to Fig. 16(a2), the plug 30E (first optical connector) provided in the optical cable 30Ea will be described. The optical cable 30Ea has an optical cable main body transmission line set consisting of two transmission lines, a transmitting side optical cable main body transmission line (transmission line outside the transmitting side connector) 39 and a receiving side optical cable main body transmission line (transmission line outside the receiving side connector) 36, as its optical cable main body transmission line. Plugs are provided on both ends of this optical cable main body transmission line set, and Fig. 16(a2) shows the plug 30E on the one end side.

[0165] The plug 30E includes a housing 31, a ferrule 32, a reflecting mirror 45, a reflecting mirror 46, a reflecting mirror 34, and a reflecting mirror 35.

[0166] The ferrule 32 is integrally formed with a lens (collimating lens) 37 for inputting light (receiving light) input from a receiving-side optical cable main body transmission line (transmission line outside the receiving-side connector) 36 arranged on the other end side of the housing 31 to a reflecting mirror 45, and a lens (condensing lens) 38 for condensing the light input from the reflecting mirror 46 and inputting it to a transmitting-side optical cable main body transmission line (transmission line outside the transmitting-side connector) 39 arranged on the other end side of the housing 31. In this case, the transmitting-side optical cable main body transmission line 39 constitutes a part of the transmitting-side transmission line (first transmission line), the receiving-side optical cable main body transmission line 36 constitutes a part of the receiving-side transmission line (second transmission line), and the receiving-side optical cable main body transmission line 36 and the transmitting-side optical cable main body transmission line 39 constitute one optical cable main body transmission line set.

[0167] Although FIG. 16( a2 ) shows one receiving-side optical cable main transmission line 36 and one transmitting-side optical cable main transmission line 39, a plurality of receiving-side optical cable main transmission lines 36 and a plurality of transmitting-side optical cable main transmission lines 39 may be provided. That is, a plurality of optical cable main transmission line sets may be provided. For example, when a plurality of optical cable main transmission line sets are provided, these optical cable main transmission line sets may be arranged side by side in the depth direction of FIG. 16 , i.e., in the left-right direction (y-axis direction) of FIG. 2 described above. In this case, each receiving-side optical cable main transmission line 36 is paired with one of the transmitting-side optical cable main transmission lines 39, and each pair of the receiving-side optical cable main transmission line 36 and the transmitting-side optical cable main transmission line 39 constitutes an optical cable main transmission line set. Each optical cable main transmission line set is provided corresponding to each communication channel (transmitting and receiving channel).

[0168] The reflecting surfaces of the reflecting mirrors 45 and 46 form a bending portion. The reflecting surface of the reflecting mirror 45 bends light (received light) input from the receiving-side optical cable main transmission line 36 and outputs it into the space formed within the housing 31. The bending angle is set to an angle at which the light (bent light) output from the reflecting mirror 45 into the space is transmitted toward the reflecting mirror 34. The reflecting surface of the reflecting mirror 46 bends light (reflected light) input from the reflecting mirror 35 and outputs it toward the transmitting-side optical cable main transmission line 39. In the illustrated example, the reflecting surfaces of the reflecting mirrors 45 and 46 are flat, but any shape may be used as long as it does not impede their function as bending portions. For example, the reflecting surface of the reflecting mirror 45 may be convex and the reflecting surface of the reflecting mirror 46 may be concave, or vice versa.

[0169] The reflecting surfaces of the reflecting mirrors 34 and 35 constitute a reflecting portion. The reflecting mirrors 34 and 35 are formed at positions facing each other inside one end of the housing 31. The reflection angle of this reflecting portion is set to an angle at which light reflected by this reflecting portion (reflected light) is transmitted toward the transmitting-side optical cable main transmission path 39 via the reflecting mirror 46.

[0170] In this case, as shown in Figure 16 (b2), the reflective surface of the reflective mirror 34 is rotated by θy31 degrees from the z-axis around the y-axis as the central axis in order to reflect light from the reflective mirror 45 upward in the figure, and the reflective surface of the reflective mirror 35 is rotated by -θy31 degrees from the z-axis around the y-axis as the central axis in order to reflect light from below in the figure toward the reflective mirror 46, as shown in Figure 16 (b2).

[0171] As shown in the figure, the operation of the plug 30E in a state where the plug 30E is not mated with the receptacle 10E, i.e., in a disconnected state, will be described. In this case, light input from the receiving-side optical cable main transmission path 36 to the ferrule 32 is collimated by the lens (collimating lens) 37, then bent by the reflecting mirror 45 and incident on the reflecting surface of the lower reflecting mirror 34. Next, the light reflected by the reflecting mirror 34 is incident on the reflecting surface of the upper reflecting mirror 35. Next, the light reflected by the reflecting mirror 35 (reflected light) is bent by the reflecting mirror 46 and focused by the lens (focusing lens) 38, and input to the transmitting-side optical cable main transmission path 39 as received light for detection, in this case, disconnected state detection light (disconnected state detection light).

[0172] In this way, an optical path is formed when the connector is not mated, and light transmitted from the receiving-side optical cable main transmission path 36 to the ferrule 32 passes through the reflecting mirrors 45, 46 that form the bending portion and the reflecting mirrors 34, 35 that form the reflecting portion, and is returned to the transmitting-side optical cable main transmission path 39. In this case, the light transmitted from the receiving-side optical cable main transmission path 36 to the ferrule 32 is not output to the outside from one end side of the housing 31, thereby achieving eye safety.

[0173] 17 shows a state in which a plug 30E is mated with a receptacle 10E. When the plug 30E is mated with the receptacle 10E, light input from the transmission path 16 in the receptacle 10E to the ferrule 12 is collimated by a lens (collimating lens) 17, passes through a reflecting mirror 25 and a reflecting mirror 46, is converged by a lens (converging lens) 38, and is input to a transmission-side optical cable main transmission path 39 in the plug 30E. When the plug 30E is mated with the receptacle 10E, light input from the reception-side optical cable main transmission path 36 in the plug 30E to the ferrule 32 is collimated by a lens (collimating lens) 37, passes through a reflecting mirror 45 and a reflecting mirror 26, is converged by a lens (converging lens) 18, and is input to a reception-side device transmission path 19 in the receptacle 10E.

[0174] In this manner, when plug 30E is mated with receptacle 10E, a mated optical path is formed connecting receptacle 10E and plug 30E. Therefore, receiving-side device internal transmission path 19 functions as a reception / detection transmission path that serves both as a reception transmission path for light transmitted from device B and as a reception transmission path for received detection light (detachment state detection light, non-connection state detection light). Here, the optical path from lens (collimating lens) 17 of receptacle 10E to lens (condensing lens) 38 of plug 30E and the optical path from lens (collimating lens) 37 of plug 30E to lens (condensing lens) 18 of receptacle 10E can be realized by the design of reflecting mirrors 25, 26, 36, and 37.

[0175] Note that detailed description of the state in which receptacle 10E of device A is connected to receptacle 10E' of device B via optical cable 30Ea will be omitted here. This state is similar to the state in which receptacle 10A of device A is connected to receptacle 10A' of device B via optical cable 30Aa (see FIG. 5), and an optical path is formed during mating that connects receptacle 10E of device A with receptacle 10E' of device B.

[0176] Further, here, detailed explanation will be omitted regarding the state in which the plug 30E provided as the first optical connector at one end of the optical cable 30Ea is engaged with the receptacle 10E of the device A, while the plug 30E' provided as the second optical connector at the other end of the optical cable 30Ea is not engaged with the receptacle 10E' of the device B (the plug 30E' side is in a detached state). This state is similar to the state in which the plug 30A provided as the first optical connector at one end of the optical cable 30Aa described above is engaged with the receptacle 10A of device A, but the plug 30A' provided as the second optical connector at the other end of the optical cable 30Aa is not engaged with the receptacle 10A' of device B (the plug 30A' side is in a detached state) (see Figure 6), and device A equipped with the receptacle 10E can detect that the plug 30E' of the optical cable 30Ea is in a detached state with respect to the receptacle 10E' of device B.

[0177] "1-1-6. Structure for returning light via a path according to an identifier when detached" Figures 18(a), (c), and (d) show an example configuration of an optical connector 60F (a receptacle 10F provided in a device, or a plug 30F provided in an optical cable).

[0178] The optical connector 60F has multiple (four in this example) sets of external connector transmission paths, each set including a transmission-side external connector transmission path and a reception-side external connector transmission path. In the receptacle 10F, the transmission path outside the transmission connector is a transmission path inside the transmission-side device, and the transmission path outside the reception-side connector is a transmission path inside the reception-side device. In the plug 30F, the transmission path outside the transmission connector is a transmission path in the transmission-side optical cable main body, and the transmission path outside the reception-side connector is a transmission path in the reception-side optical cable main body.

[0179] Figure 18(a) shows a side view of the optical connector 60F observed in the direction indicated by arrow L1 in Figure 2, Figure 18(c) shows a top view of the optical connector 60F observed in the direction indicated by arrow L2 in Figure 2, and Figure 18(d) shows a front view of the optical connector 60F observed in the direction indicated by arrow L3 in Figure 2.

[0180] The four out-of-connector transmission lines 66-1, 66-2, 66-3, and 66-4 arranged side by side in the horizontal direction in the four out-of-connector transmission line sets, and the four receiving out-connector transmission lines 69-1, 69-2, 69-3, and 69-4 arranged side by side in the horizontal direction in the four out-of-connector transmission line sets, are arranged at different positions in the vertical direction, with the transmission lines of each out-of-connector transmission line set corresponding to each other. In this example, the out-of-connector transmission line set is formed by the optically connected out-of-connector transmission lines and the receiving out-of-connector transmission lines paired in a corresponding relationship according to their identifiers. Each out-of-connector transmission line set is provided corresponding to each communication channel (transmission and reception channels). In this case, the optical connector 60F includes transmission lines within the transmitting optical connector corresponding to the transmission lines outside the transmitting connector 66-1, 66-2, 66-3, and 66-4, as well as transmission lines within the receiving optical connector corresponding to the transmission lines outside the receiving connector 69-1, 69-2, 69-3, and 69-4. Each transmission line within the transmitting optical connector is paired with one of the transmission lines within the receiving optical connector in a corresponding relationship according to the identifier, and each pair of the transmission line within the transmitting optical connector and the transmission line within the receiving optical connector constitutes an optical connector transmission line set.

[0181] The optical connector 60F has a housing 61, a ferrule 62, a prism 63, reflecting mirrors 64-1, 64-2, 64-3, and 64-4, and reflecting mirrors 65-1, 65-2, 65-3, and 65-4.

[0182] The ferrule 62 is integrally formed with lenses (collimating lenses) 67-1, 67-2, 67-3, 67-4 for collimating light (transmitted light) transmitted from transmission paths 66-1, 66-2, 66-3, 66-4 outside the transmitting connector arranged at one end of the housing 61 and inputting the light to the prism 63, and lenses (condensing lenses) 68-1, 68-2, 68-3, 68-4 for condensing the light input from the prism 63 and inputting it to transmission paths 69-1, 69-2, 69-3, 69-4 outside the receiving connector arranged at one end of the housing 61. In this case, the transmission paths 66-1, 66-2, 66-3, and 66-4 outside the transmitting connector constitute part of the transmitting transmission path (first transmission path), and the transmission paths 69-1, 69-2, 69-3, and 69-4 outside the receiving connector constitute part of the receiving transmission path (second transmission path).

[0183] The prism 63 forms a bending portion, and bends the light (transmitted light) input from the transmission paths 66-1, 66-2, 66-3, and 66-4 outside the transmitting connector, and emits the light into the space formed inside the housing 61. The bending angle is set to an angle at which the light (bent light) emitted into the space from the prism 63 is transmitted toward the reflecting mirrors 64-1, 64-2, 64-3, and 64-4.

[0184] The reflecting surfaces of the reflecting mirrors 64-1, 64-2, 64-3, and 64-4 and the reflecting mirrors 65-1, 65-2, 65-3, and 65-4 constitute reflecting sections. The reflecting mirrors 64-1, 64-2, 64-3, and 64-4 and the reflecting mirrors 65-1, 65-2, 65-3, and 65-4 are formed inside the other end of the housing 61, at positions where each reflecting mirror 64-1, 64-2, 64-3, and 64-4 faces the corresponding reflecting mirror 65-1, 65-2, 65-3, and 65-4. The reflection angle of this reflecting section is set to an angle at which light reflected by this reflecting section (reflected light) is transmitted via the prism 63 toward the transmission paths 69-1, 69-2, 69-3, and 69-4 outside the receiving connector.

[0185] In this case, when viewed from the side (see Figure 18(a)), the reflective surfaces of the reflecting mirrors 64-1, 64-2, 64-3, and 64-4 are rotated by θy11 degrees from the z-axis around the y-axis as their central axis in order to reflect light from the prism 63 upward in the figure, as shown in Figure 18(b), and the reflective surfaces of the reflecting mirrors 65-1, 65-2, 65-3, and 65-4 are rotated by -θy11 degrees from the z-axis around the y-axis as their central axis in order to reflect light from below in the figure toward the prism 63, as shown in Figure 18(b).

[0186] In this case, when viewed from the front (see Figure 18(d)), the reflective surfaces of the reflecting mirrors 64-1, 64-2, 64-3, and 64-4 are rotated by -θz11 degrees from the y-axis around the z-axis as their central axis in order to reflect the light from the prism 63 toward one of the reflecting mirrors 65-1, 65-2, 65-3, and 65-4 that correspond to the identifier of the optical connector 60F, as shown in Figure 18(e).The reflective surfaces of the reflecting mirrors 65-1, 65-2, 65-3, and 65-4 are rotated by -θz11 degrees from the y-axis around the z-axis as their central axis in order to input the light from one of the reflecting mirrors 64-1, 64-2, 64-3, and 64-4 into the receiving-side external connector transmission paths 69-1, 69-2, 69-3, and 69-4 via the prism 63, as shown in Figure 18(e).

[0187] The rotation angle -θz11 degrees associated with each of the reflecting mirrors 64-1, 64-2, 64-3, and 64-4 varies depending on which of the reflecting mirrors 65-1, 65-2, 65-3, and 65-4 the light is reflected toward. Also, the rotation angle -θz11 degrees associated with each of the reflecting mirrors 65-1, 65-2, 65-3, and 65-4 varies depending on which of the reflecting mirrors 64-1, 64-2, 64-3, and 64-4 the light is input from.

[0188] 18(d) shows an example in which transmission lines 66-1, 66-2, 66-3, and 66-4 outside the connector on the transmitting side are set to correspond to transmission lines 69-4, 69-3, 69-1, and 69-2 outside the connector on the receiving side, respectively. Note that, for simplicity of the drawing, the optical paths from the transmission lines 66-3 and 66-4 outside the connector on the transmitting side are not shown.

[0189] As shown in the figure, the operation of the optical connector 60F will be described in a state where no other optical connector is mated to the optical connector 60F, i.e., in a detached state. In this case, light input to the ferrule 62 from the transmitting-side external connector transmission paths 66-1, 66-2, 66-3, and 66-4 is collimated by lenses (collimating lenses) 67-1, 67-2, 67-3, and 67-4, and then bent by the prism 63 to be incident on the reflecting surfaces of the lower reflecting mirrors 64-1, 64-2, 64-3, and 64-4. Next, the light reflected by the reflecting mirrors 64-1, 64-2, 64-3, and 64-4 is incident on the reflecting surface of one of the reflecting mirrors 65-1, 65-2, 65-3, and 65-4 that corresponds to the identifier of the optical connector 60F. Next, the light (reflected light) reflected by the reflecting mirrors 65-1, 65-2, 65-3, and 65-4 is bent by the prism 63, and focused by lenses (focusing lenses) 68-1, 68-2, 68-3, and 68-4, and input to transmission paths 69-1, 69-2, 69-3, and 69-4 outside the receiving connector.

[0190] In this way, an optical path is formed when the connector is not mated, and light transmitted from the transmission paths 66-1, 66-2, 66-3, and 66-4 outside the transmitting connector to the ferrule 62 is returned to the transmission paths 69-1, 69-2, 69-3, and 69-4 outside the receiving connector via the prism 63, the reflecting mirrors 64-1, 64-2, 64-3, and 64-4, and the reflecting mirrors 65-1, 65-2, 65-3, and 65-4, thereby enabling a device equipped with the optical connector 60F to detect that the optical connector 60F is in a disconnected state. In this case, the light transmitted from the transmission paths 66-1, 66-2, 66-3, and 66-4 outside the connector to the ferrule 62 is not output to the outside from the other end of the housing 61, thereby achieving eye safety.

[0191] In this case, the light transmitted from the transmitting-side external connector transmission paths 66-1, 66-2, 66-3, and 66-4 to the ferrule 62 is returned to one of the receiving-side external connector transmission paths 69-1, 69-2, 69-3, and 69-4 in correspondence with the identifier of the optical connector 60F. In this case, by using the light transmitted from the transmitting-side external connector transmission paths 66-1, 66-2, 66-3, and 66-4 to the ferrule 62 as a transmission path set number identification optical signal (channel number identification optical signal), it is possible to obtain path information (route information) indicating to which of the receiving-side external connector transmission paths 69-1, 69-2, 69-3, and 69-4 the light transmitted from the transmitting-side external connector transmission paths 66-1, 66-2, 66-3, and 66-4 to the ferrule 62 has been returned, and a device equipped with the optical connector 60F (receptacle 10F) can obtain the identifier (ID) of the optical connector 60F from this path information. This identifier makes it possible to identify whether it is a receptacle or an optical cable (plug), what type of receptacle or optical cable it is, and further, at least one of the types and specifications of the devices (device A, device B, optical intermediate connection devices (optical cable, relay adapter)) that include the optical connector 60F. For example, the specifications of an optical cable include at least one of the number of transmission path sets, optical wavelength, insertion loss, fiber type, total transmission bandwidth, cable length, etc.

[0192] 19 shows an example of path information. As described above, this path information is obtained when the transmission paths 66-1, 66-2, 66-3, and 66-4 outside the transmitting connector are set to correspond to the transmission paths 69-4, 69-3, 69-1, and 69-2 outside the receiving connector, respectively. In this case, path P1 indicates the path from the transmission path 1 outside the transmitting connector to the transmission path 4 outside the receiving connector, path P2 indicates the path from the transmission path 2 outside the transmitting connector to the transmission path 3 outside the receiving connector, path P3 indicates the path from the transmission path 3 outside the transmitting connector to the transmission path 1 outside the receiving connector, and path P4 indicates the path from the transmission path 4 outside the transmitting connector to the transmission path 2 outside the receiving connector. For example, an identifier "4312" can be obtained from this path information. In this case, this identifier can also be used to obtain information such as whether it is a receptacle or a plug, and what type of receptacle or plug it is. If there are four transmission line sets, 24 patterns of identifiers can be used.

[0193] The transmission line set number identification optical signal is, for example, a pulse signal that identifies the transmission line set number (channel number) based on the number of pulses, pulse timing, pulse width, etc. However, the signal is not limited to this and may identify the transmission line set number based on a value, wavelength, etc. Furthermore, the transmission line set number identification optical signal does not change its value depending on the transmission line set number, and may be, for example, a signal of constant power. In this case, it is possible to identify the transmission line set number by performing time division processing, for example.

[0194] 20(a) to (c) show examples in which the transmission line set number identification optical signal is a pulse signal. Fig. 20(a) shows an example in which the transmission line set number is identified by the number of pulses. For example, as shown in the figure, the number of pulses of the transmission line set number identification optical signal for transmission line set 1 "TL1" is 1, the number of pulses of the transmission line set number identification optical signal for transmission line set 2 "TL2" is 2, and so on for the subsequent transmission line sets 3 "TL3" and 4 "TL4."

[0195] 20B shows an example in which the transmission line set number is identified by pulse timing. For example, as shown in the figure, the pulse timing of the transmission line set number identification optical signal for transmission line set 1 "TL1" is the earliest first timing t1, and the pulse timing of the transmission line set number identification optical signal for transmission line set 2 "TL2" is the second timing t2 which is later than the first timing t1, and the same applies to the subsequent transmission line sets 3 "TL3" and 4 "TL4".

[0196] 20(c) shows an example in which the transmission line set number is identified by pulse width. For example, as shown in the figure, the pulse width of the transmission line set number identification optical signal for transmission line set 1 "TL1" is the shortest first width w1, and the pulse width of the transmission line set number identification optical signal for transmission line set 2 "TL2" is the second width w2 that is longer than the first width w1, and the same is true for subsequent transmission line sets 3 "TL3" and 4 "TL4".

[0197] Although not shown, when the plug of the optical cable is fitted into the receptacle 10F as the optical connector 60F, light transmitted from the transmission paths within the transmitting device (transmission paths outside the transmitting connector) 66-1, 66-2, 66-3, and 66-4 on the receptacle 10F side to the ferrule 62 is collimated by lenses (collimating lenses) 67-1, 67-2, 67-3, and 67-4, and then passes through the prism 63 and the prism of the plug on one end of the optical cable, is focused by the lens (focusing lens) of the plug on one end, and is input to the transmission path of the transmitting optical cable main body of the optical cable via the plug on one end.

[0198] Furthermore, when an optical cable plug is mated with receptacle 10F as optical connector 60F, light transmitted from the receiving-side optical cable main body transmission path on the plug side to the plug-side ferrule is collimated by the plug's lens (collimating lens), passes through the plug's prism and prism 63 of receptacle 10F, is condensed by lenses (condensing lenses) 68-1, 68-2, 68-3, and 68-4, and is input to receiving-side device internal transmission paths 69-1, 69-2, 69-3, and 69-4 on the receptacle 10F side. In this way, when the optical cable plug is mated with receptacle 10F, a mated optical path is formed that connects receptacle 10F side and the plug side of the optical cable.

[0199] Here, when a plug at one end of an optical cable is engaged with a receptacle 10F as an optical connector 60F, and further, when a plug 30F as an optical connector 60F at the other end of the optical cable is not engaged with another device, for example, device B having a receptacle different from device A having receptacle 10F, or a relay device such as a relay adapter or extension cable interposed between the optical cable and device B, an optical path is established in the plug 30F at the other end of the optical cable during non-engagement, and the optical signal is transmitted to the ferrule of the plug at one end via the receiving side optical cable main body transmission path of the optical cable (transmission path outside the receiving side connector) corresponding to the identifier of the plug 30F at the other end.

[0200] Then, light transmitted from the receiving side optical cable main body transmission path of the optical cable to the ferrule on the plug side at one end is collimated by the lens (collimating lens) of the plug at one end, passes through the prism of the plug at one end and prism 63 of receptacle 10F, is focused by lenses (focusing lenses) 68-1, 68-2, 68-3, and 68-4, and is input to receiving side equipment internal transmission paths (receiving side connector external transmission paths) 69-1, 69-2, 69-3, and 69-4 on the receptacle 10F side.

[0201] This allows device A equipped with receptacle 10F to detect that plug 30F is in a disconnected state. In this case, the light transmitted from transmitting-side external connector transmission paths 66-1, 66-2, 66-3, and 66-4 to ferrule 62 is not output to the outside from the other end of housing 61 of plug 30F, thereby achieving eye safety.

[0202] In this case, by treating the light transmitted from the transmission paths 66-1, 66-2, 66-3, and 66-4 in the transmitting device on the receptacle 10F side to the ferrule 62 as a transmission path set number identification optical signal (channel number identification optical signal), it is possible to obtain path information (route information) indicating to which of the transmission paths 69-1, 69-2, 69-3, and 69-4 in the receiving device the light transmitted from the transmission paths 66-1, 66-2, 66-3, and 66-4 in the transmitting device to the ferrule 62 has been returned, and the device A equipped with the receptacle 10F can obtain the identifier (ID) of the plug 30F from this path information.

[0203] Although detailed description will be omitted, for example, if a plug at one end of an optical cable is connected to a receptacle 10F serving as an optical connector 60F, and an optical intermediate connector such as a relay adapter or an extension cable is connected to the plug at the other end of the optical cable, and the optical intermediate connector in a connected state immediately before the disconnection position is in a disconnected state at the optical connector 60F provided on the other end, device A equipped with receptacle 10F can detect that the optical connector 60F on the other end of the optical intermediate connector immediately before the disconnection position is in a disconnected state. In this case, device A equipped with receptacle 10F can detect, from the path information, the identifier (ID) of the optical connector 60F of the optical intermediate connector immediately before the disconnection position, in other words, route information which is the identifier (ID) of the optical intermediate connector immediately before the disconnection position. When receptacle 10F as optical connector 60F is detached from the plug at one end of the optical cable, it is possible to detect the route information, which is the identifier (ID) of receptacle 10F, i.e., the identifier (ID) of device A that includes receptacle 10F as optical connector 60F. Therefore, device A can detect detachment position information, which is connection relationship information and indicates the position of detachment, based on the route information.

[0204] Furthermore, when a plug at one end of an optical cable is mated with a receptacle 10F as an optical connector 60F, and the plug at the other end of the optical cable is mated with a receptacle of device B directly or via a predetermined number of optical intermediate connectors such as relay adapters or extension cables, the mated connectors work together to establish an optical path at all mated points, thereby establishing an optical path connecting devices A and B.

[0205] In the optical connector 60F shown in Figures 18(a), (c), and (d), an example is shown in which the bending portion is formed by a prism 63 and the reflecting portion is formed by the reflecting surfaces of two reflecting mirrors (reflecting mirrors 64 (64-1, 64-2, 64-3, 64-4) and reflecting mirrors 65 (65-1, 65-2, 65-3, 65-4)), but this is not limited to this. For example, it is also possible to form the bending portion by the reflecting surfaces of the reflecting mirrors. Furthermore, for example, if the bending portion is formed by a prism 63, it is also possible to form the reflecting portion by the reflecting surface of a single reflecting mirror.

[0206] "1-1-6. Structure using a relay adapter for cable connection" Figure 21 (a2) shows an example of the configuration of a relay adapter 50 for connecting optical cables, Figure 21 (a1) shows an example of the configuration of a plug 30A' as an optical connector that fits into one end (the left end in the figure) of the relay adapter 50, and Figure 21 (a3) ​​shows an example of the configuration of a plug 30A as an optical connector that fits into the other end (the right end in the figure) of the relay adapter 50.

[0207] The plug 30A' shown in Fig. 21(a1) and the plug 30A shown in Fig. 21(a3) are configured similarly to the plug 30A' on the other end side as the second optical connector and the plug 30A on one end side as the first optical connector in the optical cable 30Aa shown in Fig. 3 described above, respectively, and therefore description thereof will be omitted. Note that in Figs. 21(a1) and (a3), parts corresponding to those in Fig. 3 are denoted by the same reference numerals.

[0208] 21 shows a configuration for one transmission path set, i.e., one communication channel (transmission / reception channel), for the sake of simplicity, but a plurality of transmission path sets may be provided. For example, when a plurality of transmission path sets are provided, these transmission path sets may be arranged side by side in the depth direction of FIG. 21, i.e., in the left-right direction (y-axis direction) of FIG. 2 described above. In this case, each transmission path set is provided corresponding to each communication channel (transmission / reception channel).

[0209] 21(a2), the relay adapter 50 will be described. The relay adapter 50 has a housing 51, a reflecting mirror 52, a reflecting mirror 53, a prism 54, a prism 55, a prism 56, a reflecting mirror 57, and a reflecting mirror 58.

[0210] Reflecting mirror 52 and reflecting mirror 53 are formed at positions facing each other on the inside of one end (the left end in the figure) of housing 51. Although detailed description of reflecting mirror 52 and reflecting mirror 53 will be omitted, they function similarly to reflecting mirror 14 and reflecting mirror 15 in receptacle 10A shown in Figure 1(a1) described above, and constitute a reflecting portion. The reflection angle of this reflecting portion is set to an angle at which light reflected by this reflecting portion (reflected light) is transmitted via prisms 54-56 toward transmitting-side optical cable main body transmission path (transmission path outside the transmitting-side connector) 39 of the optical cable including plug 30A connected to the other end (the right end in the figure).

[0211] Reflecting mirror 57 and reflecting mirror 58 are formed at positions facing each other on the inside of the other end (the right end in the figure) of housing 51. Although detailed description of reflecting mirror 57 and reflecting mirror 58 will be omitted, they function similarly to reflecting mirror 14 and reflecting mirror 15 in receptacle 10A shown in FIG. 1(a1) described above, and constitute a reflecting portion. The reflection angle of this reflecting portion is set to an angle at which light reflected by this reflecting portion (reflected light) is transmitted via prisms 56-54 toward receiving-side optical cable main body transmission path (transmission path outside receiving-side connector) 36 of the optical cable including plug 30A' connected to one end (the left end in the figure).

[0212] Prisms 54 to 56 function in the same manner as prism 13 in the receptacle 10A shown in FIG. 1(a1) described above and constitute a bent portion. Prisms 54 to 56 bend the light (input light) input from the transmission-side optical cable main body transmission path 39 of the optical cable provided with the plug 30A' connected to one end side (left end side in the figure), and emit it into the space on the other end side (right end side in the figure) formed within the housing 51. In this case, the bending angle is set to an angle such that the light (bent light) emitted from prism 56 into the space on the other end side is transmitted toward the reflection mirror 57.

[0213] Further, prisms 54 to 56 bend the light (input light) input from the reception-side optical cable main body transmission path 36 of the optical cable provided with the plug 30A connected to the other end side (right end side in the figure), and emit it into the space on the one end side (left end side in the figure) formed within the housing 51. In this case, the bending angle is set to an angle such that the light (bent light) emitted from prism 54 into the space on the one end side is transmitted toward the reflection mirror 52.

[0214] In this relay adapter 50, in the transmission direction, prisms 54 to 56 and reflection mirrors 57 and 58 constitute an optical connector similar to the receptacle 10A shown in FIG. 1(a1). In the space on one end side (left end side in the figure) of prism 54, there are a transmission-side connector external transmission path and a reception-side connector external transmission path as space transmission paths (not shown) that function in the same manner as the in-device transmission-side transmission path 16 and the in-device reception-side transmission path 19. Also, in this relay adapter 50, in the reception direction, prisms 56 to 54 and reflection mirrors 52 and 53 constitute an optical connector similar to the receptacle 10A shown in FIG. 1(a1). In the space on the other end side (right end side in the figure) of prism 56, there are a transmission-side connector external transmission path and a reception-side connector external transmission path as space transmission paths (not shown) that function in the same manner as the in-device transmission-side transmission path 16 and the in-device reception-side transmission path 19.

[0215] FIG. 22 shows a state where the plug 30A' is fitted to one end side of the relay adapter 50 and the plug 30A is not fitted to the other end side of the relay adapter 50, that is, a detached state on the other end side of the relay adapter 50.

[0216] In this case, light transmitted from the transmitting-side optical cable main transmission path (transmission path outside the transmitting-side connector) 39 of the optical cable having the plug 30A' fitted to one end of the relay adapter 50 to the ferrule 32' is collimated by the lens (collimating lens) 37', then bent by the prism 33' and further by the prisms 54 to 56, and is incident on the reflecting surface of the reflecting mirror 57 at the lower end of the relay adapter 50. Next, the light reflected by the reflecting mirror 57 is incident on the reflecting surface of the reflecting mirror 58 at the upper end of the relay adapter 50. Next, the light reflected by the reflecting mirror 58 (reflected light) is bent by the prisms 56 to 54 and further by the prism 33' of the plug 30A', is focused by the lens (focusing lens) 38', and is input to the receiving-side optical cable main transmission path (transmission path outside the receiving-side connector) 36 of the plug 30A'.

[0217] In this way, an optical path is formed when the optical cable is not mated, and light transmitted from the transmitting-side optical cable main transmission path 39 of the optical cable including the plug 30A' mated to one end of the relay adapter 50 to the ferrule 32' is returned to the receiving-side optical cable main transmission path 36 of the optical cable including the plug 30A' mated to one end of the relay adapter 50 via the prisms 33', 54-56 that form the bending portion and the reflecting mirrors 57, 58 that form the reflecting portion. This allows device A, which has a receptacle mated with an optical cable having an optical connector mated to the relay adapter 50 at its other end, to detect that the other end of the relay adapter 50 is in a disconnected state. In this case, light transmitted from the transmitting-side optical cable main transmission path 39 of the plug 30A' mated to one end of the relay adapter 50 to the ferrule 32' is not output to the outside from the other end of the housing 51 of the relay adapter 50, thereby achieving eye safety.

[0218] 18, a device A having a receptacle mated with an optical cable having an optical connector mated with the relay adapter 50 at its other end can acquire an identifier of the other end of the relay adapter 50 based on light (transmission path set number identification optical signal) returned to each receiving-side intra-device transmission path 19 in a plurality of intra-device transmission path sets. This also enables the device A to recognize that a detachment has occurred at the other end of the relay adapter 50. The relay adapter 50 can be applied not only to optical communication systems that both detect detachment and acquire identifiers as described above, but also to optical communication systems that only detect detachment or acquire identifiers.

[0219] FIG. 23 shows a state in which the plug 30A' is fitted to one end of the relay adapter 50 and the plug 30A is fitted to the other end of the relay adapter 50. In FIG.

[0220] In this case, light transmitted from the transmitting-side optical cable main body transmission path 39 on the plug 30A' side to the ferrule 32' is collimated by the lens (collimating lens) 37' of the plug 30A', then passes through the prism 33' of the plug 30A', the prisms 54 to 56 of the relay adapter 50, and further through the prism 33 of the plug 30A, and is focused by the lens (focusing lens) 38 of the plug 30A, and is input to the transmitting-side optical cable main body transmission path 39 on the plug 30A side.

[0221] In this case, light transmitted from the receiving-side optical cable main transmission path 36 on the plug 30A side to the ferrule 32 is collimated by the lens (collimating lens) 37 of the plug 30A, passes through the prism 33 of the plug 30A, the prisms 56 to 54 of the relay adapter 50, and further through the prism 33' of the plug 30A', is condensed by the lens (condensing lens) 38' of the plug 30A', and is input to the receiving-side optical cable main transmission path 36 on the plug 30A' side. In this manner, when the plug 30A' is fitted to one end of the relay adapter 50 and the plug 30A is fitted to the other end of the relay adapter 50, an optical path is formed during fitting that connects the plug 30A' side and the plug 30A side.

[0222] 21(a2) shows an example in which the bending portion is configured by the prisms 54 to 56, but the present invention is not limited to this. For example, the bending portion may be configured by the reflecting surface of a reflecting mirror.

[0223] 1-2. Example of the configuration of an optical communication system 1-2-1. A system in which two devices are connected by one optical cable FIG. 24 shows an example of the configuration of an optical communication system 100A. In this optical communication system 100A, a device (device A) 200 and a device (device B) 300 that constitutes a communication device to be connected among devices to be connected are connected via an optical cable 400 that constitutes an optical intermediate connection device among devices to be connected. Here, the device 200 and the device 300 each constitute an optical communication device (optical communication device).

[0224] The optical cable 400 corresponds to a plurality of transmission path sets (communication channels) numbered 1 to N (N is an integer of 2 or more). The optical cable 400 is configured such that a plug 402 as a first optical connector is provided at one end of an optical cable main body 401, and a plug 403 as a second optical connector is provided at the other end of the optical cable main body 401.

[0225] The optical cable main body 401 has an optical cable main body transmission line set consisting of two optical cable main body transmission lines, a transmitting side optical cable main body transmission line (transmission line outside the transmitting side connector) 401T and a receiving side optical cable main body transmission line (transmission line outside the receiving side connector) 401R, corresponding to each transmission line set. The optical cable 400 has a cross cable structure, in which the transmitting side optical cable main body transmission line 401T and the receiving side optical cable main body transmission line 401R cross each other midway along the optical cable main body 401.

[0226] Here, the transmitting-side optical cable main transmission line 401T is a transmission line that transmits light (optical signal) as transmitted light from the device 200 to the device 300, and the receiving-side optical cable main transmission line 401R is a transmission line that transmits light (optical signal) as received light from the device 300 to the device 200. The transmitting-side optical cable main transmission line 401T and the receiving-side optical cable main transmission line 401R are each composed of optical fibers.

[0227] In Figure 24, for the sake of simplicity, only one optical cable main body transmission line set, for example the transmitting side optical cable main body transmission line 401T and the receiving side optical cable main body transmission line 401R corresponding to the first optical cable main body transmission line set, is shown out of the multiple optical cable main body transmission line sets 1 to N (N is an integer of 2 or more).

[0228] The optical cable 400 may be a ribbon-type optical cable in which the optical fibers are arranged in a row, or a bundle-type optical cable in which the optical fibers are arranged in a cylindrical resin tube. The optical cable 400 may also include a multi-core optical fiber having multiple cores corresponding to multiple channels within a single optical fiber.

[0229] The optical cable 400 has plugs 402 and 403 at one end and the other end, respectively. Here, the optical cable 400 constitutes an optical intermediate connector, and the plugs 402 and 403 constitute intermediate connector optical connectors, respectively. The plug 402 of the optical cable 400 is fitted into the receptacle 201 of the device 200, and the plug 403 of the optical cable 400 is fitted into the receptacle 301 of the device 300. This mechanically and optically connects the device 200 and the optical cable 400, and also mechanically and optically connects the optical cable 400 and the device 300.

[0230] Here, receptacle 201 and receptacle 301 each constitute a communication device optical connector. In this case, from the perspective of device 200, receptacle 201 constitutes its own device optical connector, and receptacle 301 constitutes a target communication device optical connector, and from the perspective of device 300, receptacle 301 constitutes its own device optical connector, and receptacle 201 constitutes a target communication device optical connector. Note that the own device optical connector is configured to be indirectly connectable to the target communication device optical connector via an optical intermediate connector including at least one optical cable. Also, the own device optical connector is configured to be indirectly connectable to the target communication device optical connector via a connection with an intermediate connector optical connector of one optical cable of one or more optical intermediate connectors including at least one optical cable configured to be connectable to the own device optical connector.

[0231] In addition to the above-mentioned receptacle 201, device 200 has control unit 202, communication signal input / output unit 203, signal processing unit 204, transmitting unit 205T, receiving unit 205R, presentation unit 206, and storage unit 207. Transmitting unit 205T is connected to receptacle 201 via a transmission path within the transmitting device (transmission path outside the transmitting connector) 210T. Furthermore, receiving unit 205R is connected to receptacle 201 via a transmission path within the receiving device (transmission path outside the receiving connector) 210R.

[0232] Here, a transmitter 205T and a receiver 205R are provided corresponding to each of the first to Nth transmission path sets. To simplify the drawing, Fig. 24 shows only two of the first to Nth transmission path sets, for example, a transmitter / receiver set consisting of a first transmitter 205T (Tx1) and a first receiver 205R (Rx1) corresponding to the first transmission path set (first communication channel), and a transmitter / receiver set consisting of a second transmitter 205T (Tx2) and a second receiver 205R (Rx2) corresponding to the second transmission path set (second communication channel). Note that one or more transmitters are paired with one or more receivers, and each pair of transmitters and receivers constitutes a transmitter / receiver set.

[0233] The control unit 202 controls the operation of each unit of the device 200. The presentation unit 206 is composed of a display, a speaker, etc., and displays the operating status of the device 200 and warnings to the user on the display, or outputs audio warnings from the speaker. The storage unit 207 stores various information.

[0234] The signal processing unit 204 performs signal processing to convert the transmission data into a signal suitable for optical communication and sends it to a light emitting element (laser, etc.) constituting the transmission unit 205 T. The signal processing unit 204 also performs predetermined signal processing on the received data sent from a light receiving element (photodiode, etc.) constituting the reception unit 205 R.

[0235] Transmission data acquired from an external device connected via the Internet or the like, or output from a predetermined internal location, such as the control unit 202 or a recording unit (not shown), is supplied to the signal processing unit 204 via the communication signal input / output unit 203. Furthermore, received data obtained by the signal processing unit 204 is appropriately supplied to a predetermined internal location, such as an external device connected via the Internet or a recording unit (not shown), via the control unit 202 or the communication signal input / output unit 203. Note that in control communications such as connection / non-connection detection, data is exchanged between the signal processing unit 204 and the control unit 202, and actual data such as image data is exchanged between the signal processing unit 204 and the control unit 202 via the communication signal input / output unit 203 and the signal processing unit 204.

[0236] Although detailed description will be omitted, device 300 is configured similarly to device 200 described above, and in addition to receptacle 301 described above, includes control unit 302, communication signal input / output unit 303, signal processing unit 304, transmitting unit 305T, receiving unit 305R, presentation unit 306, and storage unit 307. Transmitting unit 305T is connected to receptacle 301 via a transmission path within the receiving device (transmission path outside the receiving connector) 310R. Furthermore, receiving unit 305R is connected to receptacle 301 via a transmission path within the transmitting device (transmission path outside the transmitting connector) 310T.

[0237] 25 shows all the transmission paths in the optical communication system 100A. Light transmitted from device (device A) 200 in the direction of device (device B) 300 (light transmitted by device A) is transmitted light, and the transmission path that transmits this transmitted light is the transmitting-side transmission path (first transmission path). Also, light transmitted from device (device B) 300 in the direction of device (device A) 200 (light transmitted by device B) is received light, and the transmission path that transmits this received light is the receiving-side transmission path (second transmission path). Here, the transmitting side and receiving side are defined from the perspective of device (device A) 200.

[0238] Device (device A) 200 has, as its device transmission paths, intra-connector (receptacle) transmission paths (transmission-side connector internal transmission path, reception-side connector internal transmission path) that are transmission paths within receptacle 201, and intra-device transmission paths (transmission-side device internal transmission path 210T, reception-side device internal transmission path 201R) that are transmission paths outside receptacle 201. Optical cable 400 also has, as its optical cable transmission paths, intra-connector (plug) transmission paths (transmission-side connector internal transmission path, reception-side connector internal transmission path) that are transmission paths within plugs 402, 403 at both ends, and optical cable main body transmission paths (transmission-side optical cable main body transmission path 401T, reception-side optical cable main body transmission path 401R) that are transmission paths within optical cable main body 401. In addition, the device (device B) 300 has, as device transmission paths, transmission paths within the connector (receptacle) that are transmission paths within the receptacle 301 (transmission path within the transmitting connector, transmission path within the receiving connector), and intra-device transmission paths that are transmission paths outside the receptacle 301 (transmission path within the transmitting device 310T, transmission path within the receiving device 310R).

[0239] When optical cable 400 is attached to device 200 by a user operation, plug 402 of optical cable 400 is mated with receptacle 201 of device 200, and plug 402 and receptacle 201 work together to establish an optical path when mated. Here, receptacle 201 and plug 402 are configured similarly to receptacle 10A and plug 30A shown in Fig. 1 above, receptacle 10B and plug 30B shown in Fig. 7 above, receptacle 10E and plug 30E shown in Fig. 16 above, or optical connector 60F shown in Fig. 18 above. Note that although the configurations in Figs. 1, 7, and 16 show one communication channel (one transmission path set), as explained above, these configurations may include multiple communication channels.

[0240] Furthermore, when optical cable 400 is attached to device 300 by a user operation, plug 402 of optical cable 400 is fitted into receptacle 301 of device 300. Here, receptacle 301 and plug 403 are configured similarly to receptacle 10A and plug 30A shown in Fig. 1 above, receptacle 10B and plug 30B shown in Fig. 7 above, receptacle 10E and plug 30E shown in Fig. 16 above, or optical connector 60F shown in Fig. 18 above, etc. Note that although the configurations in Figs. 1, 7, and 16 show one communication channel (one transmission path set), as explained above, these configurations may include multiple communication channels.

[0241] The device 300 has the same configuration as the device 200, so the following description will focus on the device 200 and omit the description of the device 300.

[0242] For example, after power-on, before starting communication of actual data such as images and audio with the device 300, the control unit 202 of the device 200 performs a first, second, or third connection detection process to detect connection relationship information indicating whether each transmission path set (communication channel), i.e., each transmitter / receiver set, is in a connected or disconnected state, and performs communication processing of the actual data based on the detection results. Here, the first, second, or third connection detection process is performed based on the reception status of the receiver 205R. Note that even when communication of actual data is interrupted, the first, second, or third connection detection process may be performed automatically or in response to a user instruction, and communication processing of the actual data may be performed based on the detection results.

[0243] Here, the connected state refers to a state in which the receptacle 201 of the device 200 and the receptacle 301 of the device 300, which is the target communication device, are mechanically and optically connected. The unconnected state refers to a state in which the devices are not connected, and includes at least one of a disconnected state in which they are not mechanically or optically connected, and a disconnected state in which they are mechanically connected but not optically connected. Therefore, the connection relationship information can include at least one of disconnection information indicating a disconnected state between two optical connectors that should be mated, among the multiple optical connectors between the device's own optical connector and the target communication device optical connector, and disconnection information indicating a disconnected state.

[0244] For example, in the first connection detection process, an optical signal is output from each transmitter 205T (Tx1, Tx2, ...) of the device 200, and this optical signal is sent to the receptacle 201 via the transmission path 210T inside the transmitting device, and further to the device 300 via the transmission path 401T of the transmitting optical cable main body of the optical cable 400. In this state, the control unit 202 of the device 200 detects connection relationship information (here, disconnection information) indicating whether the device is in a connected state or a disconnected state (here, disconnected) as follows.

[0245] First, when an optical path during non-engagement is established and an optical signal from the device 200 is received as received light for detection in at least one receiving unit 205R (Rx1, Rx2, ...) via the transmission path 210R within the receiving device, the control unit 202 of the device 200 determines that the optical cable 400 has been detached. Furthermore, when an optical path during engagement is established and an optical signal from the device 200 is not received by any receiving unit 205R, the control unit 202 of the device 200 determines that all transmission path sets are in a connected state. In other words, the control unit 202 determines that the device 200 and the device 300 are in a connected state.

[0246] Details of this process will be described later using the flowchart shown in Fig. 33. Here, the disconnection information constitutes connection relationship information that is detected when the connection state between receptacle 201 of device 200 and receptacle 301 of device 300 is at least optically disconnected.

[0247] Furthermore, in a second connection detection process as another example of the connection detection process, for example, optical signals are output from the transmitters 205T (Tx1, Tx2, ...) of the device 200, and these optical signals are sent to the receptacle 201 via the transmission path 210T inside the device on the transmitting side, and further to the device 300 via the transmission path 401T of the optical cable 400 on the transmitting side. In addition, in this second connection detection process, optical signals are output from the transmitters 305T (Tx1, Tx2, ...) of the device 300, and these optical signals are sent to the receptacle 301 via the transmission path 310R inside the device on the receiving side, and further to the device 200 via the transmission path 401R of the optical cable 400 on the receiving side. In this state, the control unit 202 of the device 200 detects whether the device is in a connected state or a disconnected state as follows.

[0248] First, the control unit 202 of the device 200 determines that the optical cable 400 has been detached when an optical path is established when the device is not engaged and an optical signal from the device 200 is received as received light for detection by at least one receiving unit 205R (Rx1, Rx2, ...).

[0249] Furthermore, when any of the receiving units 205R (Rx1, Rx2, ...) receives neither an optical signal from the device 200 nor an optical signal from the device 300, the control unit 202 of the device 200 determines that there is a break in the corresponding transmission path set of the optical cable 400. That is, even though it is determined that an optical path is established when mated because no optical signal is received from the device 200, it determines that there is a break because no optical signal is received from the device 300.

[0250] Furthermore, when an optical path is established during mating, and optical signals from the device 200 are not received by all receiving units 205R but optical signals from the device 300 are received, the control unit 202 of the device 200 determines that all transmission path sets are in a connected state. In other words, the control unit 202 determines that the device 200 and the device 300 are in a connected state. That is, since optical signals from the device 200 are not received, it is determined that an optical path is established during mating, and since optical signals from the device 300 are received, it is determined that no disconnection has occurred, and therefore it is determined that the device is in a connected state.

[0251] Details of this processing will be described later using the flowchart shown in Fig. 34. Here, the disconnection and disconnection constitute connection relationship information that is detected when the connection state between receptacle 201 of device 200 and receptacle 301 of device 300 is at least optically disconnected. Furthermore, in the above description, the optical signals are simply optical signals from device 200 and device 300, but if these optical signals are output simultaneously, it is possible to use a pilot optical signal or optical signals with different wavelengths (frequencies) to distinguish them from one another.

[0252] Furthermore, in a third connection detection process as another example of the connection detection process, for example, optical signals are output from the transmitters 205T (Tx1, Tx2, ...) of the device 200, and these optical signals are sent to the receptacle 201 via the transmission path 210T inside the transmitting device and further to the device 300 side via the transmitting side optical cable main transmission path 401T of the optical cable 400. In this third connection detection process, optical signals are output from the transmitters 305T (Tx1, Tx2, ...) of the device 300, and these optical signals are sent to the receptacle 301 via the transmission path 310R inside the receiving device and further to the device 200 side via the receiving side optical cable main transmission path 401R of the optical cable 400.

[0253] Furthermore, in this third connection detection process, in response to reception of an optical signal from the device 200 by each receiving unit 305R (Rx1, Rx2, ...) of the device 300, a reception confirmation optical signal (acknowledge optical signal) indicating reception of the optical signal from the device 200 is output from each transmitting unit 305T (Tx1, Tx2, ...) of the device 300, and this reception confirmation optical signal is sent to the receptacle 301 via the receiving-side internal device transmission path 310R and further to the device 200 side via the receiving-side optical cable main body transmission path 401R of the optical cable 400. In this state, the control unit 202 of the device 200 detects whether it is in a connected state or a disconnected state as follows.

[0254] First, the control unit 202 of the device 200 determines that the optical cable 400 has been detached when an optical path is established when the device is not engaged and an optical signal from the device 200 is received as received light for detection by at least one receiving unit 205R (Rx1, Rx2, ...).

[0255] Furthermore, if neither an optical signal from the device 200 nor an optical signal from the device 300 is received by any of the receiving units 205R (Rx1, Rx2, ...), the control unit 202 of the device 200 determines that there is a break in at least one of the receiving side transmission line and the transmitting side transmission line in the corresponding transmission line set of the optical cable 400.

[0256] That is, when an optical signal from the device 200 is not received by the receiving unit 205R, this also includes a case where the plug 403 is not engaged with the receptacle 301 of the device 300 and is detached, but the transmission-side optical cable main transmission path 401T is broken. In this case, even though the plug 403 is not engaged with the receptacle 301 of the device 300 and is detached, the transmission-side optical cable main transmission path 401T is broken, so that an optical path is not established when the plug 403 is not engaged with the receptacle 301 of the device 300, and the optical signal from the device 200 is not received by the receiving unit 205R.

[0257] In this case, since the plug 403 is not mated with the receptacle 301 of the device 300 but is disengaged, the receiving unit 205R does not receive an optical signal from the device 300. The case where the receiving unit 205R does not receive an optical signal from the device 200 also includes a case where disengagement has not occurred and an optical path is established when mated. In this case, if the receiving-side optical cable main transmission path 401R is broken, the receiving unit 205R does not receive an optical signal from the device 300.

[0258] Therefore, if any of the receiving units 205R (Rx1, Rx2, ...) receives neither an optical signal from the device 200 nor an optical signal from the device 300, the control unit 202 of the device 200 determines that there is a break in at least one of the receiving side transmission line and the transmitting side transmission line in the corresponding transmission line set of the optical cable 400.

[0259] Furthermore, if any of the receiving units 205R (Rx1, Rx2, ...) does not receive an optical signal from the device 200 but receives an optical signal from the device 300, but does not receive a reception confirmation optical signal from the device 300 indicating that the optical signal from the device 200 has been received, the control unit 202 of the device 200 determines that the transmitting side optical cable main transmission line 401T in the corresponding transmission line set is broken. Furthermore, if all of the receiving units 205R do not receive an optical signal from the device 200 but receive an optical signal from the device 300, and moreover receive a reception confirmation optical signal from the device 300 indicating that the optical signal from the device 200 has been received, the control unit 202 of the device 200 determines that all of the transmission line sets are in a connected state. In other words, the device 200 and the device 300 are in a connected state.

[0260] Details of this processing will be described later using the flowchart shown in Fig. 35. Here, the disconnection and disconnection constitute connection relationship information that is detected when the connection state between receptacle 201 of device 200 and receptacle 301 of device 300 is at least optically disconnected. Furthermore, in the above description, the optical signals are simply optical signals from device 200 and device 300, but if these optical signals are output simultaneously, it is possible to use a pilot optical signal or optical signals with different wavelengths (frequencies) to distinguish them from one another.

[0261] In the above, the first, second, and third connection detection processes on the device 200 side have been described, but similar processes may also be performed on the device 300 side, although a detailed description will be omitted.

[0262] "1-2-2. System in which two devices are connected by two optical cables connected in series" Figure 26 shows an example of the configuration of an optical communication system 100B. In this Figure 26, parts corresponding to those in Figure 24 are given the same reference numerals, and detailed explanations thereof will be omitted as appropriate. In this optical communication system 100B, device (device A) 200 and device (device B) 300 are connected via optical cables 400-1 and 400-2.

[0263] The optical cable 400-1 corresponds to a plurality of transmission line sets numbered 1 to N (N is an integer equal to or greater than 2), similar to the optical cable 400 in the optical communication system 100A in Fig. 24. In order to simplify the drawing, Fig. 26 shows only one transmission line set out of the plurality of transmission line sets numbered 1 to N (N is an integer equal to or greater than 2), for example, the transmission line set consisting of the transmitting side optical cable main body transmission line 401-1T and the receiving side optical cable main body transmission line 401-1R corresponding to the first transmission line set.

[0264] This optical cable 400-1 has a plug 402-1 and a receptacle 403-1 at one end and the other end, respectively. The optical cable 400-1 is configured such that a plug 402-1 serving as a first optical connector is provided at one end of the optical cable main body 401-1, and a receptacle 403-1 serving as a second optical connector is provided at the other end of the optical cable main body 401-1. The optical cable 400-1 also has a cross cable structure, in which a transmitting-side optical cable main body transmission path 401-1T and a receiving-side optical cable main body transmission path 401-1R cross each other midway along the optical cable main body 401-1. Here, the optical cable 400-1 constitutes an optical intermediate connector, and the plug 402-1 and the receptacle 403-1 each constitute an intermediate connector optical connector.

[0265] The optical cable 400-2 also corresponds to a plurality of transmission line sets numbered 1 to N (N is an integer equal to or greater than 2), similar to the optical cable 400 in the optical communication system 100A in Fig. 24. In order to simplify the drawing, Fig. 26 shows only one transmission line set, for example, the transmitting side optical cable main transmission line 401-2T and the receiving side optical cable main transmission line 401-2R, which correspond to the first transmission line set, out of the plurality of transmission line sets numbered 1 to N (N is an integer equal to or greater than 2).

[0266] The optical cable 400-2 has a plug 402-2 and a plug 403-2 at one end and the other end, respectively. The optical cable 400-2 is configured such that a plug 402-2 serving as a first optical connector is provided at one end of the optical cable main body 401-2, and a plug 403-2 serving as a second optical connector is provided at the other end of the optical cable main body 401-2. The optical cable 400-2 also has a cross cable structure, in which the transmitting optical cable main body transmission path 401-2T and the receiving optical cable main body transmission path 401-2R cross each other midway along the optical cable main body 401-2. Here, the optical cable 400-2 also constitutes an optical intermediate connector, and the plug 402-2 and the plug 403-2 each constitute an intermediate connector optical connector.

[0267] When the optical cable 400-1 is attached to the device 200 by a user operation, the plug 402-1 of the optical cable 400-1 is fitted into the receptacle 201 of the device 200. When the optical cable 400-2 is connected to the optical cable 400-1 by a user operation, the plug 402-2 of the cable 400-2 is fitted into the receptacle 403-1 of the optical cable 400-1. When the optical cable 400-2 is attached to the device 300 by a user operation, the plug 403-2 of the optical cable 400-2 is fitted into the receptacle 301 of the device 300. As a result, receptacle 201, which is the optical connector of the device itself, is configured to be mechanically and optically connectable to receptacle 301, which is the optical connector of the communication device to be connected, which is configured to be connectable to one optical cable of the optical intermediate connection devices via one or more optical intermediate connection devices including at least one optical cable.

[0268] Here, receptacle 201 and plug 402-1, and receptacle 403-1 and plug 402-2 are respectively configured in the same manner as receptacle 10A and plug 30A shown in Fig. 1 above, receptacle 10B and plug 30B shown in Fig. 7 above, receptacle 10E and plug 30E shown in Fig. 16 above, or optical connector 60F shown in Fig. 18 above. Note that although the configurations in Fig. 1, 7, and 16 show one communication channel (one transmission line set), as explained above, these configurations may include multiple communication channels.

[0269] In the optical communication system 100B shown in FIG. 26 , similarly to the optical communication system 100A shown in FIG. 24 , the control unit 202 of the device 200 performs a first, second, or third connection detection process to detect whether each transmission path set (communication channel) is in a connected or disconnected state after power-on, etc., before starting communication of actual data such as images and audio with the device 300, and performs communication processing based on the detection result. Here, similarly to the optical communication system 100A shown in FIG. 24 , the first, second, or third connection detection process is performed based on the reception state of the receiving unit 205R. In this optical communication system 100B, disconnection can occur in the receptacle 201 of the device 200, the receptacle 403-1 of the optical cable 400-1, or the plug 403-2 of the optical cable 400-2. Similar processing may also be performed on the device 300 side.

[0270] In the optical communication system 100B shown in FIG. 26, the devices 200 and 300 are connected via two optical cables, optical cable 400-1 and optical cable 400-2, which are connected in series, but it is also possible to similarly connect the devices 200 and 300 via more optical cables.

[0271] "1-2-3. System in which two devices are connected by multiple optical cables connected in series via relay adapters" Figure 27 shows an example configuration of an optical communication system 100C. In Figure 27, parts corresponding to those in Figure 24 are given the same reference numerals, and detailed descriptions thereof will be omitted as appropriate. In this optical communication system 100C, device (device A) 200 and device (device B) 300 are connected via optical cables 400-3, 400-4, and 400-5. In this case, optical cables 400-3 and 400-4 are connected using relay adapter 500-1, and optical cables 400-4 and 400-5 are connected using relay adapter 500-2.

[0272] The optical cables 400-3, 400-4, and 400-5 each correspond to a plurality of transmission line sets (communication channels) numbered 1 to N (N is an integer of 2 or more), similar to the optical cable 400 in the optical communication system 100A in Fig. 24. For simplicity of the drawing, Fig. 27 shows only one transmission line set out of the plurality of transmission line sets numbered 1 to N (N is an integer of 2 or more), for example, the optical cable main body transmission line set consisting of transmitting side optical cable main body transmission lines 401-3T, 401-4T, and 401-5T and receiving side optical cable main body transmission lines 401-3R, 401-4R, and 401-5R corresponding to the first transmission line set (first communication channel).

[0273] The optical cable 400-3 has a plug 402-3 and a plug 403-3 at one end and the other end, respectively. The optical cable 400-3 is configured such that a plug 402-3 as a first optical connector is provided at one end of the optical cable main 401-3, and a receptacle 403-3 as a second optical connector is provided at the other end of the optical cable main 401-3. The optical cable 400-3 also has a cross cable structure, in which a transmitting-side optical cable main transmission path 401-3T and a receiving-side optical cable main transmission path 401-3R cross each other midway along the optical cable main 401-3. Here, the optical cable 400-3 constitutes an optical intermediate connector, and the plug 402-3 and the plug 403-3 each constitute an intermediate connector optical connector.

[0274] The optical cable 400-4 is provided with a plug 402-4 and a plug 403-4 at one end and the other end, respectively. The optical cable 400-4 is configured such that a plug 402-4 as a first optical connector is provided at one end of the optical cable main 401-4, and a receptacle 403-4 as a second optical connector is provided at the other end of the optical cable main 401-4. The optical cable 400-4 has a cross cable structure, in which the transmitting optical cable main transmission path 401-4T and the receiving optical cable main transmission path 401-4R cross each other midway along the optical cable main 401-4. Here, the optical cable 400-4 constitutes an optical intermediate connector, and the plug 402-4 and the plug 403-4 each constitute an intermediate connector optical connector.

[0275] The optical cable 400-5 is provided with a plug 402-5 and a plug 403-5 at one end and the other end, respectively. The optical cable 400-5 is configured such that a plug 402-5 as a first optical connector is provided at one end of the optical cable main 401-5, and a receptacle 403-5 as a second optical connector is provided at the other end of the optical cable main 401-5. The optical cable 400-5 has a cross cable structure, in which the transmitting optical cable main transmission path 401-5T and the receiving optical cable main transmission path 401-5R cross each other midway along the optical cable main 401-5. Here, the optical cable 400-5 constitutes an optical intermediate connector, and the plug 402-5 and the plug 403-5 each constitute an intermediate connector optical connector.

[0276] Although detailed description of the relay adapters 500-1 and 500-2 will be omitted, each is configured similarly to the relay adapter 50 shown in Fig. 21. Here, the relay adapters 500-1 and 500-2 each constitute an optical intermediate connector, and have optical connectors (intermediate connector optical connectors) at one end and the other end for fitting plugs thereto.

[0277] When the optical cable 400-3 is attached to the device 200 by a user operation, the plug 402-3 of the optical cable 400-3 is fitted into the receptacle 201 of the device 200. When the optical cables 400-3 and 400-4 are connected by a user operation, the plug 403-3 of the optical cable 400-3 is fitted into the optical connector portion at one end of the relay adapter 500-1, and the plug 402-4 of the optical cable 400-4 is fitted into the optical connector portion at the other end of the relay adapter 500-1. When the optical cables 400-4 and 400-5 are connected, the plug 403-4 of the optical cable 400-4 is fitted into the optical connector portion at one end of the relay adapter 500-2, and the plug 402-5 of the optical cable 400-5 is fitted into the optical connector portion at the other end of the relay adapter 500-2. Furthermore, when the optical cable 400 - 5 is attached to the device 300 , the plug 403 - 5 of the optical cable 400 - 5 is fitted into the receptacle 301 of the device 300 .

[0278] Here, receptacle 201 and plug 402-3, and receptacle 301 and plug 403-5 are respectively configured similarly to receptacle 10A and plug 30A shown in Fig. 1 above, receptacle 10B and plug 30B shown in Fig. 7 above, receptacle 10E and plug 30E shown in Fig. 16 above, or optical connector 60F shown in Fig. 18 above. Note that although the configurations in Fig. 1, 7, and 16 show one communication channel (one transmission line set), as explained above, these configurations may include multiple communication channels.

[0279] Furthermore, plug 403-3, relay adapter 500-1, and plug 402-4, and plug 403-4, relay adapter 500-2, and plug 402-5 are configured similarly to plug 30A', relay adapter 50, and plug 30A in Fig. 21. Note that although the configuration in Fig. 21 shows one communication channel, as explained above, these configurations may be provided with multiple communication channels.

[0280] As described above, when the optical cable plug 30A' is fitted to one end of the relay adapter 50 and the optical cable plug 30A is fitted to the other end, an optical path is formed during mating that connects the transmitting-side optical cable main body transmission path (transmission path outside the transmitting connector) 39 on the plug 30A' side to the transmitting-side optical cable main body transmission path (transmission path outside the transmitting connector) 39 on the plug 30A' side, and an optical path is formed during mating that connects the receiving-side optical cable main body transmission path (transmission path outside the receiving connector) 36 on the plug 30A' side to the receiving-side optical cable main body transmission path (transmission path outside the receiving connector) 36 on the plug 30A' side (see FIG. 23 ). In this case, because the transmitting-side optical path and the receiving-side optical path cross within the relay adapter 50, the relay adapter 50 behaves similarly to a cross cable.

[0281] Therefore, when the optical cables 400-3 and 400-4 are connected using the relay adapter 500-1, an optical path is formed when mated that connects the transmitting side optical cable main transmission line 401-3T of the optical cable 400-3 and the transmitting side optical cable main transmission line 401-4T of the optical cable 400-4, and an optical path is also formed when mated that connects the receiving side optical cable main transmission line 401-4R of the optical cable 400-4 and the receiving side optical cable main transmission line 401-3R of the optical cable 400-3. Furthermore, when the optical cables 400-4 and 400-5 are connected using the relay adapter 500-1, an optical path is formed when mated that connects the transmitting side optical cable main transmission path 401-4T of the optical cable 400-4 and the transmitting side optical cable main transmission path 401-5T of the optical cable 400-5, and an optical path is also formed when mated that connects the receiving side optical cable main transmission path 401-5R of the optical cable 400-5 and the receiving side optical cable main transmission path 401-4R of the optical cable 400-4.

[0282] In the optical communication system 100C shown in FIG. 27, similarly to the optical communication system 100A shown in FIG. 24, the control unit 102 of the device 200 performs a first, second, or third connection detection process to detect whether each transmission path set is in a connected or disconnected state, for example, after power-on, before starting communication of actual data such as images and audio with the device 300, and performs communication processing based on the detection result. Here, similarly to the optical communication system 100A shown in FIG. 24, the first, second, or third connection detection process is performed based on the reception state of the receiving unit 205R. In this optical communication system 100C, disconnection can occur at each of the connection points: the receptacle 201 of the device 200, the plug 403-3 of the optical cable 400-3, the optical connector at the other end of the relay adapter 500-1, the plug 403-4 of the optical cable 400-4, the optical connector at the other end of the relay adapter 500-2, and the plug 403-5 of the optical cable 400-5. The same process may also be performed on the device 300 side.

[0283] In the optical communication system 100C shown in FIG. 27, the equipment 200 and the equipment 300 are connected via three optical cables, namely, optical cable 400-3, optical cable 400-4, and optical cable 400-5, which are connected in series, but it is also possible to similarly connect the equipment 200 and the equipment 300 via even more optical cables.

[0284] 1-2-4. System for Detecting Disconnections Using Optical Circulators FIG. 28 shows a configuration example of an optical communication system 100D. In FIG. 28, parts corresponding to those in FIG. 27 are assigned the same reference numerals, and detailed descriptions thereof will be omitted where appropriate. In this optical communication system 100D, a device (device A) 200D and a device (device B) 300 are connected via optical cables 400-3, 400-4, and 400-5. In this case, the optical cables 400-3 and 400-4 are connected using a relay adapter 500-1, and the optical cables 400-4 and 400-5 are connected using a relay adapter 500-2. Note that the device 200D and the device 300 may be connected by a single optical cable, as in the optical communication system 100A of FIG. 24, or may be connected by multiple optical cables without using a relay adapter, as in the optical communication system 100B of FIG. 26.

[0285] Receptacle 201 and plug 402-3, and receptacle 301 and plug 403-5 are respectively configured in the same manner as receptacle 10A and plug 30A shown in Fig. 1 above, receptacle 10B and plug 30B shown in Fig. 7 above, receptacle 10E and plug 30E shown in Fig. 16 above, or optical connector 60F shown in Fig. 18 above. Note that although the configurations in Fig. 1, 7, and 16 show one communication channel (one transmission line set), as explained above, these configurations may include multiple communication channels.

[0286] Furthermore, plug 403-3, relay adapter 500-1, and plug 402-4, and plug 403-4, relay adapter 500-2, and plug 402-5 are configured similarly to plug 30A', relay adapter 50, and plug 30A in Fig. 21. Note that although the configuration in Fig. 21 shows one communication channel, as explained above, these configurations may be provided with multiple communication channels.

[0287] In addition to receptacle 201, device 200D includes control unit 202, communication signal input / output unit 203, signal processing unit 204, transmitter 205T, receiver 205R, receiver 205r, optical circulator 208, presentation unit 206, and memory unit 207. Here, transmitter 205T, receiver 205R, receiver 205r, and optical circulator 208 are provided corresponding to each of the first to Nth transmission line sets described above. In order to simplify the drawing, FIG. 28 shows only transmitter 205T, receiver 205R, receiver 205r, and optical circulator 208 corresponding to two transmission line sets, for example, the first transmission line set (first communication channel) and the second transmission line set (second communication channel), out of the first to Nth transmission line sets (communication channels).

[0288] Here, transmitter 205T is connected to port 1 of optical circulator 208 via transmission path 210T in the transmitting device, port 2 of this optical circulator 208 is connected to receptacle 201 via transmission path 210Tr in the transmitting device and separation detection device, and port 3 of this optical circulator 208 is connected to receiver 205r via transmission path 210r in the detection-only device. Also, receiver 205R is connected to receptacle 201 via transmission path 210R in the receiving device.

[0289] When light (optical signal) is being output from the transmitter 205T and there is a break in any of the transmission-side optical cable main transmission lines of the optical cables 400-3, 400-4, and 400-5, reflected light is generated at the break point, and this reflected light is input to port 2 of the optical circulator 208 via the broken transmission-side optical cable main transmission line, output from port 3, and input to the receiver 205r. Therefore, the controller 202 can detect a break in the transmission-side optical cable main transmission line based on the reception state of the receiver 205r.

[0290] Furthermore, if there is a break in the transmission path between port 2 of optical circulator 208 and receptacle 201 (transmission path 210Tr in the transmission side and detachment detection device), reflected light is similarly generated at the break location, and this reflected light is input to port 2 of optical circulator 208 via transmission path 210Tr in the transmission side and detachment detection device, output from port 3, and input to receiver 205r. Therefore, based on the reception state of receiver 205r, controller 202 can detect a break in the transmission side transmission path, including when a break has occurred in the transmission path between port 2 of optical circulator 208 and receptacle 201 (transmission path 210Tr in the transmission side and detachment detection device).

[0291] For example, after power-on, the control unit 202 of the device 200D performs a fourth, fifth, or sixth connection detection process to detect whether each transmission path set (communication channel) is in a connected state or a disconnected state before starting communication of actual data such as images and audio with the device 300, and performs communication processing of the actual data based on the detection result. Note that even when communication of the actual data is interrupted, the fourth, fifth, or sixth connection detection process may be performed automatically or in response to a user instruction, and communication processing of the actual data may be performed based on the detection result.

[0292] Here, the connected state refers to a state in which receptacle 201 of device 200D and receptacle 301 of device 300, which is the communication device to be connected, are mechanically and optically connected. Also, the unconnected state refers to a state in which no connection has been made, and includes at least one of a disconnection in which there is no mechanical or optical connection, and a disconnection in which there is a mechanical connection but no optical connection.

[0293] For example, in the fourth connection detection process, an optical signal is output from each transmitter 205T (Tx1, Tx2, ...) of device 200, and this optical signal is sent to device 300 via the transmitting-side internal device transmission path 210T, circulator 208, and transmitting-side and disconnection detection internal device transmission path 210Tr, and further via the transmitting-side transmission path including the transmitting-side optical cable main body transmission paths 401-3T, 401-4T, and 401-5T of optical cables 400-3, 400-4, and 400-5. In this state, control unit 202 of device 200D detects whether it is in a connected state or a disconnected state (disconnected in this case) as follows.

[0294] First, when an optical path during non-engagement is established and an optical signal from the device 200D is received as detection-use received light by at least one receiver 205R (Rx1, Rx2, ...) via the transmission path 210R within the receiving device, the control unit 202 of the device 200D determines that either the optical cable (optical cable 400-3, optical cable 400-4, optical cable 400-5) or the device 300 has been disconnected. Furthermore, when an optical path during engagement is established and an optical signal from the device 200D is not received by any receiver 205R (Rx1, Rx2, ...), the control unit 202 of the device 200D determines that all transmission path sets are in a connected state. In other words, the control unit 202 determines that the device 200D and the device 300 are in a connected state.

[0295] Details of this process will be described later using the flowchart shown in Fig. 33. Here, the disconnection constitutes connection relationship information that is detected when the connection state between receptacle 201 of device 200D and receptacle 301 of device 300 is at least optically disconnected.

[0296] Furthermore, in a fifth connection detection process as another example of the connection detection process, for example, an optical signal is output from each transmitter 205T (Tx1, Tx2, ...) of the device 200D, and this optical signal is sent to the device 300 side via the transmitting-side internal device transmission path 210T, the circulator 208, and the transmitting-side and disconnection detection internal device transmission path 210Tr, and further via the transmitting-side transmission path including the transmitting-side optical cable main body transmission paths 401-3T, 401-4T, and 401-5T of the optical cables 400-3, 400-4, and 400-5. In this state, the control unit 202 of the device 200D detects whether it is in a connected state or a disconnected state as follows.

[0297] First, when an optical path is established when the device is not engaged, and an optical signal from the device 200D is received as received light for detection by at least the receiving unit 205R (Rx1, Rx2, ...), the control unit 202 of the device 200D determines that either the optical cable (optical cable 400-3, optical cable 400-4, optical cable 400-5) or the device 300 has been detached.

[0298] Furthermore, if an optical signal from the device 200D is not received by any of the receiving units 205R (Rx1, Rx2, ...) but an optical signal from the device 200D is received by the corresponding receiving unit 205r (rx1, rx2, ...), the control unit 202 of the device 200D determines that there is a break in the optical cable (optical cable 400-3, optical cable 400-4, optical cable 400-5) or the corresponding transmission path set of the transmission path 210Tr within the transmitting and detecting device.

[0299] Furthermore, when an optical path is established during mating, and optical signals from the device 200D are not received by any of the receiving units 205R, and further, optical signals from the device 200D are not received by any of the receiving units 205r, the control unit 202 of the device 200D determines that all transmission path sets are in a connected state, i.e., the device 200D and the device 300 are in a connected state.

[0300] Details of this process will be described later using the flowchart shown in Fig. 36. Here, the disconnection or disconnection constitutes connection relationship information that is detected when the connection state between receptacle 201 of device 200D and receptacle 301 of device 300 is at least optically disconnected.

[0301] Furthermore, for example, in a sixth connection detection process as another example of the connection detection process, an optical signal is output from each transmitting unit 205T (Tx1, Tx2, ...) of the device 200D, and this optical signal is sent to the device 300 side via the transmitting side internal transmission path 210T, the circulator 208, and the transmitting side and detachment detection internal transmission path 210Tr to the receptacle 201, and further via the transmitting side transmission path including the transmitting side optical cable main body transmission paths 401-3T, 401-4T, and 401-5T of the optical cables 400-3, 400-4, and 400-5.

[0302] Furthermore, in this sixth connection detection process, in response to reception of an optical signal from device 200 by each receiving unit 305R (Rx1, Rx2, ...) of device 300, a reception confirmation optical signal (acknowledge optical signal) indicating reception of an optical signal from device 200D is output from each transmitting unit 305T (Tx1, Tx2, ...) of device 300, and this reception confirmation optical signal is sent to the device 200 side via the receiving side internal device transmission path 310R to the receptacle 301 and further via the receiving side optical cable main body transmission paths 401-5R, 401-4R, 401-3R of the optical cables 400-5, 400-4, 400-3. In this state, the control unit 202 of device 200D detects whether it is in a connected state or a disconnected state as follows.

[0303] First, when an optical path is established when the device is not engaged, and an optical signal from the device 200D is received as received light for detection by at least the receiving unit 205R (Rx1, Rx2, ...), the control unit 202 of the device 200D determines that either the optical cable (optical cable 400-3, optical cable 400-4, optical cable 400-5) or the device 300 has been detached.

[0304] Furthermore, if an optical signal from device 200D is not received by any of receiving units 205R (Rx1, Rx2, ...) but an optical signal from device 200D is received by the corresponding receiving unit 205r (rx1, rx2, ...), the control unit 202 of device 200D determines that there is a break in the transmitting side transmission line of at least one of the corresponding transmission line sets among the transmitting side and detecting internal device transmission line 210Tr between circulator 208 and receptacle 201, optical cable 400-3, optical cable 400-4, and optical cable 400-5.

[0305] Furthermore, if an optical signal from device 200D is not received by any of receiving units 205R (Rx1, Rx2, ...), and furthermore, an optical signal from device 200D is not received by the corresponding receiving unit 205r (rx1, rx2, ...), and furthermore, a reception confirmation optical signal indicating that the optical signal from device 200D has been received from device 300 by that receiving unit 205R, the control unit 202 of device 200D determines that there is a break in the optical cable (optical cable 400-3, optical cable 400-4, optical cable 400-5) or the receiving side transmission line in the corresponding transmission line set of the internal transmission line of the device.

[0306] Furthermore, when an optical path is constructed at the time of engagement, and optical signals from the device 200D are not received by any of the receiving units 205R, and further, optical signals from the device 200D are not received by any of the receiving units 205r, but reception confirmation optical signals indicating that optical signals from the device 200D have been received by all of the receiving units 205R from the device 300, the control unit 202 of the device 200D determines that all transmission path sets are in a connected state. That is, the control unit 202 determines that the device 200D and the device 300 are in a connected state.

[0307] Details of this process will be described later using the flowchart shown in Figure 37. Here, disconnection and disconnection constitute connection relationship information that is detected when the connection state between receptacle 201 of device 200D and receptacle 301 of device 300 is at least optically disconnected. Also, the fourth, fifth, and sixth connection detection processes on the device 200D side have been described above, but although detailed description will be omitted, device 300 may be configured using a circulator like device 200D, and similar processes may also be performed on the device 300 side.

[0308] 1-2-5. System with a dedicated detection transmission path FIG. 29 shows a configuration example of an optical communication system 100E. In FIG. 29, parts corresponding to those in FIG. 24 are assigned the same reference numerals, and detailed descriptions thereof will be omitted where appropriate. In this optical communication system 100E, a device (device A) 200E and a device (device B) 300E are connected via optical cables 400-6, 400-7, and 400-8. In this case, the optical cables 400-6 and 400-7 are connected using a relay adapter 500-3, and the optical cables 400-7 and 400-8 are connected using a relay adapter 500-4. Note that the device 200E and the device 300E may be connected by a single optical cable, as in the optical communication system 100A of FIG. 24, or may be connected by multiple optical cables without using a relay adapter, as in the optical communication system 100B of FIG. 25.

[0309] The optical cables 400-6, 400-7, and 400-8 correspond to a plurality of transmission path sets (communication channels), numbered 1 through N (N is an integer equal to or greater than 2), respectively. These optical cables 400-6, 400-7, and 400-8 each have three transmission paths corresponding to each transmission path set: receiving-side optical cable main body transmission paths 401-6R, 401-7R, and 401-8R; first transmitting-side optical cable main body transmission paths 401-6T, 401-7T, and 401-8T; and second transmitting-side optical cable main body transmission paths 401-6r, 401-7r, and 401-8r as optical cable main body transmission paths dedicated to detection.

[0310] Here, the first transmitting-side optical cable main transmission lines 401-6T, 401-7T, and 401-8T are transmission lines that transmit light (optical signals) from device 200E to device 300E, and the receiving-side optical cable main transmission lines 401-6R, 401-7R, and 401-8R are transmission lines that transmit light (optical signals) from device 300E to device 200E. Furthermore, the detection-dedicated optical cable main transmission lines 401-6r, 401-7r, and 401-8r are transmission lines that transmit (return) reflected light from the detachment point when detachment occurs. The first transmitting-side optical cable main transmission lines 401-6T, 401-7T, 401-8T, the receiving-side optical cable main transmission lines 401-6R, 401-7R, 401-8R, and the detection-only optical cable main transmission lines 401-6r, 401-7r, 401-8r are each composed of optical fibers. In order to simplify the drawing, Fig. 29 shows only one transmission line set out of the first to Nth (N is an integer of 2 or more) optical cable main transmission line sets, for example, the first transmitting-side optical cable main transmission lines 401-6T, 401-7T, 401-8T, the receiving-side optical cable main transmission lines 401-6R, 401-7R, 401-8R, and the detection-only optical cable main transmission lines 401-6r, 401-7r, 401-8r corresponding to the first optical cable main transmission line set.

[0311] The optical cable 400-6 has a plug 402-6 and a plug 403-6 at one end and the other end, respectively. Here, the optical cable 400-6 constitutes an optical intermediate connector, and the plugs 402-6 and 403-6 constitute intermediate connector optical connectors, respectively. Although detailed description of these plugs 402-6 and 403-6 is omitted, they are configured similarly to the plugs 30C and 30C' shown in Figures 9 and 10 or the plug 30D shown in Figure 14, and the reflection angle is set so that, upon removal, reflected light is transmitted toward the detection-dedicated optical cable main transmission line (corresponding to the detection-dedicated optical cable main transmission line 44 in Figure 9(a2)).

[0312] Furthermore, optical cable 400-7 has plugs 402-7 and 403-7 at one end and the other end, respectively. Here, optical cable 400-7 constitutes an optical intermediate connector, and plugs 402-7 and 403-7 constitute an intermediate connector optical connector, respectively. Furthermore, optical cable 400-8 has plugs 402-8 and 403-8 at one end and the other end, respectively. Here, optical cable 400-8 constitutes an optical intermediate connector, and plugs 402-8 and 403-8 constitute an intermediate connector optical connector, respectively. These plugs 402-7, 403-7, 402-8, and 403-8 are also configured in the same manner as plugs 30C and 30C' shown in FIG. 10.

[0313] Although detailed description of the relay adapters 500-3 and 500-4 will be omitted, they are each configured similarly to the relay adapter 50 shown in Fig. 21 described above. Here, the relay adapters 500-3 and 500-4 each constitute an optical intermediate connector and have intermediate connector optical connectors, which are optical connectors into which plugs are fitted, at one end and the other end. The optical connectors at one end and the other end of the relay adapters 500-3 and 500-4 are configured to have two reflecting mirrors like the relay adapter 50 shown in Fig. 21, or to have one reflecting mirror like the receptacle 10C and plug 30C shown in Fig. 9, and the reflection angle is set so that the reflected light is transmitted toward the detection-dedicated optical cable main transmission path described above.

[0314] In addition to the receptacle 201, the device 200E includes a control unit 202, a communication signal input / output unit 203, a signal processing unit 204, a transmitter 205T, a receiver 205R, a receiver 205r, a presentation unit 206, and a storage unit 207. The transmitter 205T, the receiver 205R, and the receiver 205r are provided corresponding to the first to Nth transmission path sets (communication channels) described above, respectively. For simplicity of illustration, FIG. 29 shows only two of the first to Nth transmission path sets, for example, the transmitter 205T (Tx1, Tx2), the receiver 205R (Rx1, Rx2), and the receiver 205r (rx1, rx2) corresponding to the first and second transmission path sets.

[0315] Receptacle 201 has a configuration similar to that of receptacle 10C shown in Fig. 9. Transmitting unit 205T is connected to receptacle 201 via transmission path 210T in the transmitting device (corresponding to transmission path 16 in the transmitting device in Fig. 9(a1)), receiving unit 205R is connected to receptacle 201 via first transmission path 210R in the receiving device (corresponding to first transmission path 19 in the receiving device in Fig. 9(a1)), and receiving unit 205r is connected to receptacle 201 via detection-dedicated transmission path 210r in the device (corresponding to transmission path 24 in the detection-dedicated device in Fig. 9(a1)) as a second transmission path in the receiving device.

[0316] Although detailed explanation of device 300E is omitted, it is configured in the same manner as device 200E described above, and in addition to receptacle 301, it has a control unit 302, a communication signal input / output unit 303, a signal processing unit 304, a transmitting unit 305T, a receiving unit 305R, a transmitting unit 305r, a presentation unit 306, and a memory unit 307.

[0317] When the optical cable 400-6 is attached to the device 200E by a user operation, the plug 402-6 of the optical cable 400-6 is fitted into the receptacle 201 of the device 200E. When the optical cables 400-6 and 400-7 are connected by a user operation, the plug 403-6 of the optical cable 400-6 is fitted into the optical connector portion at one end of the relay adapter 500-3, and the plug 402-7 of the optical cable 400-7 is fitted into the optical connector portion at the other end of the relay adapter 500-3. When the optical cables 400-7 and 400-8 are connected by a user operation, the plug 403-7 of the optical cable 400-7 is fitted into the optical connector portion at one end of the relay adapter 500-4, and the plug 402-8 of the optical cable 400-8 is fitted into the optical connector portion at the other end of the relay adapter 500-4. Furthermore, when the optical cable 400-8 is attached to the device 300E by a user operation, the plug 403-8 of the optical cable 400-8 is fitted into the receptacle 301 of the device 300E.

[0318] For example, after power-on, the control unit 202 of the device 200E performs a seventh, eighth, or ninth connection detection process to detect whether each transmission path set (communication channel) is in a connected state or a disconnected state before starting communication of actual data such as images and audio with the device 300E, and performs communication processing based on the detection result. Note that even when communication of actual data is interrupted, the seventh, eighth, or ninth connection detection process may be performed automatically or in response to a user instruction, and communication processing of the actual data may be performed based on the detection result.

[0319] Here, the connected state refers to a state in which receptacle 201 of device 200E and receptacle 301 of device 300E, which is the communication device to be connected, are mechanically and optically connected. Also, the unconnected state refers to a state in which connection is not possible, and includes at least one of a disconnection in which there is no mechanical or optical connection, and a disconnection in which there is a mechanical connection but no optical connection.

[0320] For example, in the seventh connection detection process, an optical signal is output from each transmitter 205T (Tx1, Tx2, ...) of the device 200E, and this optical signal is sent to the receptacle 201 via the transmission path 210T inside the transmitting device, and further to the device 300E via the transmission path including the transmitting side optical cable main transmission paths 401-6T, 401-7T, and 401-8T of the optical cables 400-6, 400-7, and 400-8. In this state, the control unit 202 of the device 200E detects whether it is in a connected state or a disconnected state (disconnected in this case) as follows.

[0321] First, when an optical path during non-engagement is established and an optical signal from the device 200E is received as received light for detection by at least one receiver 205r (rx1, rx2, ...) via the detection-dedicated internal transmission path 210R, the control unit 202 of the device 200E determines that either the optical cable (optical cable 400-6, optical cable 400-7, optical cable 400-8) or the device 300E has been disconnected. Furthermore, when an optical path during engagement is established and an optical signal from the device 200E is not received by any receiver 205r (rx1, rx2, ...), the control unit 202 of the device 200E determines that all transmission path sets are in a connected state. In other words, the device 200E and the device 300E are in a connected state.

[0322] Details of this process will be described later using the flowchart shown in Fig. 38. Here, the disconnection constitutes connection relationship information that is detected when the connection state between receptacle 201 of device 200D and receptacle 301 of device 300 is at least optically disconnected.

[0323] Furthermore, in an eighth connection detection process as another example of the connection detection process, for example, optical signals are output from the transmitters 205T (Tx1, Tx2, ...) of the device 200E, and these optical signals are sent to the receptacle 201 via the transmission path 210T within the transmitting device and further to the device 300E via a transmission path (first transmission path) including the transmitting optical cable main transmission paths 401-6T, 401-7T, and 401-8T of the optical cables 400-6, 400-7, and 400-8. In this case, the optical signals sent from the device itself are returned to the detection-dedicated transmission path 210r within the device not only in a connected state but also in a disconnected state, and are therefore not returned to the first receiving-side transmission path 210R within the device itself. Therefore, the optical signals sent from the transmitters 205T (Tx1, Tx2, ...) of the device 200E do not need to be distinguishable from the optical signals from the device 300E.

[0324] In addition, in this eighth connection detection process, an optical signal is transmitted from the transmitter 305T (Tx1, Tx2, ...) of the device 300E, and this optical signal is sent to the device 200E side via the receptacle 301 and further via the receiving side transmission path (second transmission path) including the receiving side optical cable main transmission paths 401-8R, 401-7R, and 401-6R of the optical cables 400-8, 400-7, and 400-6. In this state, the control unit 202 of the device 200 detects whether it is in a connected state or a non-connected state as follows.

[0325] First, when an optical signal is received by at least one receiving unit 205r (rx1, rx2, ...), the control unit 202 of the device 200E determines that an optical cable (optical cable 400-6, optical cable 400-7, optical cable 400-8) is disconnected. Also, when an optical signal from the device 200E is not received by any receiving unit 205r (rx1, rx2, ...) and an optical signal from the device 300E is not received by the corresponding receiving unit 205R (Rx1, Rx2, ...), the control unit 202 of the device 200E determines that the corresponding transmission path set of the optical cable (optical cable 400-8, 400-7, 400-6) is disconnected. Furthermore, if none of the receiving units 205r (rx1, rx2, ...) receives an optical signal from the device 200E, and all of the receiving units 205R (Rx1, Rx2, ...) receives an optical signal from the device 300E, it is determined that all of the transmission path sets are in a connected state. That is, it is determined that the device 200E and the device 300E are in a connected state.

[0326] Details of this process will be described later using the flowchart shown in Fig. 39. Here, the disconnection or disconnection constitutes connection relationship information that is detected when the connection state between receptacle 201 of device 200E and receptacle 301 of device 300E is at least optically disconnected.

[0327] Furthermore, for example, in a ninth connection detection process as another example of the connection detection process, an optical signal is output from each transmitting unit 205T (Tx1, Tx2, ...) of the device 200E, and this optical signal is sent to the device 300E side via the transmission path 210T inside the transmitting device, to the receptacle 201, and further via the transmitting side transmission path (first transmission path) including the transmitting side optical cable main body transmission paths 401-6T, 401-7T, 401-8T of the optical cables 400-6, 400-7, 400-8. Furthermore, in this ninth connection detection process, an optical signal is transmitted from the transmitter 305T (Tx1, Tx2, ...) of the device 300E, and this optical signal is sent to the receptacle 301 via the transmission path 310R inside the receiving device, and further to the device 200E side via the receiving side transmission path (second transmission path) including the receiving side optical cable main body transmission paths 401-8R, 401-7R, and 401-6R of the optical cables 400-8, 400-7, and 400-6.

[0328] In addition, in this ninth connection detection process, in response to reception of an optical signal from the device 200 by each receiving unit 305R (Rx1, Rx2, ...) of the device 300, a reception confirmation optical signal (acknowledge optical signal) indicating reception of the optical signal from the device 200 is output from each transmitting unit 305T (Tx1, Tx2, ...) of the device 300, and this reception confirmation optical signal is sent to the device 200E side via the receiving side internal device transmission path 310R to the receptacle 301 and further via the receiving side transmission path (second transmission path) including the receiving side optical cable main body transmission paths 401-8R, 401-7R, and 401-6R of the optical cables 400-8, 400-7, and 400-6. In this state, the control unit 202 of the device 200E detects whether it is in a connected state or a disconnected state as follows.

[0329] First, when an optical signal is received by at least one receiving unit 205r (rx1, rx2, ...), the control unit 202 of the device 200E determines that an optical cable (optical cable 400-6, optical cable 400-7, optical cable 400-8) is disconnected. Also, when an optical signal is not received by any of the receiving units 205r (rx1, rx2, ...) and an optical signal is not received by the corresponding receiving unit 205R (Rx1, Rx2, ...), the control unit 202 of the device 200E determines that at least one of the receiving side transmission line and the transmitting side transmission line in the corresponding transmission line set of the optical cable 400 in the corresponding transmission line set of the optical cable (optical cable 400-6, optical cable 400-7, optical cable 400-8) is disconnected.

[0330] That is, cases in which the optical signal from the device 200E is not received by the receiving unit 205r include, for example, a case in which the plug 403-8 is not mated with the receptacle 301 of the device 300E and is detached, but at least one of the detection-dedicated optical cable main transmission paths 401-6r, 401-7r, and 401-8r is broken. In this case, even though the plug 403-8 is not mated with the receptacle 301 of the device 300E and is detached, at least one of the detection-dedicated optical cable main transmission paths 401-6r, 401-7r, and 401-8r is broken, so that a non-mated optical path is not established, and the optical signal from the device 200E is not received by the receiving unit 205r.

[0331] In this case, since the plug 403-8 is not mated with the receptacle 301 of the device 300E but is disengaged, the receiving unit 205R does not receive the optical signal from the device 300E. Also, when the receiving unit 205r does not receive the optical signal from the device 200E, this includes cases where disengagement has not occurred and an optical path is established when mated. In this case, if at least one of the receiving-side optical cable main transmission paths 401-6R, 401-7R, and 401-8R is broken, the optical signal from the device 300E is not received.

[0332] Therefore, if an optical signal is not received by any of the receiving units 205r (rx1, rx2, ...) and an optical signal is not received by the corresponding receiving unit 205R (Rx1, Rx2, ...), the control unit 202 of the device 200E determines that there is a break in at least one of the receiving side transmission line and the transmitting side transmission line in the corresponding transmission line set of the optical cable (optical cable 400-6, optical cable 400-7, optical cable 400-8).

[0333] Furthermore, if an optical signal is not received by any of the receiving units 205r (rx1, rx2, ...) and an optical signal is received by the corresponding receiving unit 205R (Rx1, Rx2, ...) (thus, the receiving-side optical cable main transmission line and the transmission line within the receiving-side device are not broken), but a reception confirmation optical signal indicating that an optical signal has been received from the device 300E is not received (thus, the device 300E has not received an optical signal from the device 200E), the control unit 202 of the device 200E determines that the transmitting-side optical cable main transmission line in the corresponding transmission line set is broken. Furthermore, if an optical signal is not received by all of the receiving units 205r (rx1, rx2, ...) and an optical signal is received by the receiving unit 205R (Rx1, Rx2, ...) and a reception confirmation optical signal indicating that an optical signal has been received from the device 300E is received, the control unit 202 of the device 200E determines that all of the transmission line sets are in a connected state. In other words, it is determined that the device 200E and the device 300E are in a connected state.

[0334] Details of this process will be described later using the flowchart shown in Figure 40. Here, disconnection and disconnection constitute connection relationship information that is detected when the connection state between receptacle 201 of device 200E and receptacle 301 of device 300E is at least optically disconnected. Also, although the seventh, eighth, or ninth connection detection process on the device 200E side has been described above, similar processes may also be performed on the device 300E side, although detailed description will be omitted.

[0335] 30 shows an example of a processing procedure including a connection detection process and a communication process performed in the optical communication systems 100A to 100E described above, as well as the subsequent communication process, etc. This processing procedure is performed, for example, after power-on, before starting communication of actual data such as images and audio, or when communication of the actual data is interrupted, that is, when a problem occurs, either automatically or by user operation.

[0336] First, in step ST1, the control unit 202 starts processing, for example, when the power is turned on. Next, in step ST2, the control unit 202 performs a connection detection process. This connection detection process detects whether the device is in a connected state or a disconnected state. As described above, the disconnected state can include at least one of a disconnection and a disconnection. However, a configuration may be possible in which only one of a disconnection and a disconnection can be detected. Even if a configuration is possible in which both a disconnection and a disconnection can be distinguished and detected, the two may not be distinguished and the device may be detected as a disconnected state and the user may be notified of only the disconnected state. Note that a disconnection can include a disconnection of either an optical cable, which is a connection target device mated with device A (e.g., device 200), or another connection target device (relay adapter or device B) connected via that optical cable. Furthermore, a disconnection can include a disconnection at either the transmitting transmission path or the receiving transmission path.

[0337] If it is determined in the connection detection process of step ST2 that the device is in a disconnected state, the control unit 202 notifies the user of the disconnected state in step ST3. In this case, for example, the control unit 202 notifies the user by displaying or outputting a sound indicating that the device is in a disconnected state on the presentation unit 206. After the process of step ST3, the control unit 202 ends the process in step ST4.

[0338] Furthermore, if it is determined in the connection detection process of step ST2 that the device is in a connected state, the control unit 202 sets communication settings according to the connection state in step ST5, and then performs communication processing in step ST6. If a problem occurs in this communication processing, the control unit 202 stops communication of actual data in step ST7, and then returns to the connection detection processing of step ST2, either automatically or by user operation. Here, problems include the receiving unit 205R no longer receiving optical signals. Furthermore, although communication of actual data is automatically stopped in step ST7, a notification urging the user to stop communication of actual data may be issued. If the communication processing is to be terminated, the control unit 202 terminates the processing in step ST4.

[0339] The flowchart in Figure 31 shows another example of a processing procedure for connection detection, which is performed before starting communication of actual data such as images and audio after power-on, or when communication of the actual data is interrupted, i.e., when a problem occurs, in the optical communication systems 100A to 100E described above, and is performed automatically or by user operation, as well as subsequent communication processing, etc. In Figure 31, parts corresponding to those in Figure 30 are indicated by the same reference numerals. Note that Figure 31 distinguishes between disconnection and disconnection, which were not distinguished in Figure 30.

[0340] First, in step ST1, the control unit 202 starts processing, for example, when the power is turned on. Next, in step ST2, the control unit 202 performs a connection detection process. In this connection detection process, the control unit 202 detects whether the device is in a connected state or a disconnected state. As described above, the disconnected state includes both disconnection and disconnection.

[0341] If it is determined in the connection detection process of step ST2 that at least one transmission path set (communication channel) has been disconnected, the control unit 202 notifies the user of the disconnection in step ST3A. That is, even if the mating is incomplete and at least one transmission path set has been disconnected (not physically connected), it is determined to be a disconnection because it is desirable to reconnect the transmission path set. However, if there is a transmission path set that is not determined to be a disconnection, it is possible not to determine that a disconnection has occurred by performing communication using only the transmission path set that is not determined to be a disconnection.

[0342] In this case, for example, the control unit 202 notifies the user by displaying or outputting a sound indicating that the device has been detached on the presentation unit 206. After the process of step ST3A, the control unit 202 ends the process in step ST4. When the user is notified of the detachment, he or she can check the connections of each mating point and change the detached (disconnected state) to a connected state.

[0343] Furthermore, if it is determined in the connection detection process of step ST2 that at least one transmission path set has a disconnection, the control unit 202 notifies the user of the disconnection in step ST3B. In this case, for example, the control unit 202 notifies the user by causing the presentation unit 206 to display or output a sound indicating that a disconnection has occurred. In this case, in a configuration example in which it is possible to determine which transmission path set has a disconnection, and further, which transmission path has a disconnection, individually, it is also possible to notify the user. After the process of step ST3B, the control unit 202 ends the process in step ST4. When the user is notified of the disconnection, the user can replace the optical cable with another one and change the disconnection (disconnected state) to a connected state.

[0344] Furthermore, if it is determined in the connection detection process of step ST2 that all transmission path sets are in a connected state, the control unit 202 sets communication settings according to the connection state in step ST5, and then performs communication processing in step ST6. If a problem occurs in this communication processing, the control unit 202 stops communication of actual data in step ST7, and then returns to the connection detection process of step ST2 automatically or by user operation. If the communication processing is to be ended, the control unit 202 ends the processing in step ST4.

[0345] The flowchart in Fig. 32 shows yet another example of a processing procedure for connection detection processing, which is performed automatically or by user operation in the above-mentioned optical communication systems 100A to 100E, for example, after power-on, before starting communication of actual data such as images and audio, or when communication of the actual data is interrupted, i.e., when a problem occurs, as well as subsequent communication processing, etc. In Fig. 32, parts corresponding to those in Fig. 30 and Fig. 31 are denoted by the same reference numerals.

[0346] First, in step ST1, the control unit 202 starts processing, for example, when the power is turned on. Next, in step ST2, the control unit 202 performs a connection detection process. In this connection detection process, the control unit 202 distinguishes between a connected state and a disconnected state. As described above, the disconnected state includes both a disconnection and a broken line.

[0347] If it is determined in the connection detection process of step ST2 that at least one of the transmission path sets has been disconnected, the control unit 202 notifies the user of the disconnection in step ST3A. In this case, for example, the control unit 202 notifies the user by displaying or audibly outputting the disconnection on the presentation unit 206. After the process of step ST3A, the control unit 202 ends the process in step ST4. When the user is notified of the disconnection, he or she can check the connections of each mating point and change the disconnection (disconnected state) to a connected state.

[0348] Furthermore, if it is determined in the connection detection process of step ST2 that at least one of the transmission path sets has been disconnected, the control unit 202 notifies the user of the disconnection in step ST3B. In this case, for example, the control unit 202 notifies the user by displaying or audibly outputting the fact that the line has been disconnected on the presentation unit 206. In this case, in a configuration example in which it is possible to individually determine which transmission path set has been disconnected, and further, which transmission path has been disconnected, it is also possible to notify the user of the disconnected transmission path.

[0349] Next, in step ST8, the control unit 202 determines whether or not a transmission line set that is not broken is to be used. Here, a transmission line set that is not broken means, for example, a transmission line set in which neither the sending side transmission line nor the receiving side transmission line is broken, and a transmission line set in which only either the sending side transmission line or the receiving side transmission line is broken is a transmission line set in which a break has occurred.

[0350] The control unit 202 may determine whether or not to use a transmission line set that is not disconnected, for example, based on a setting made in advance by a user, or based on a setting made by a user in response to the user being notified of the disconnection in step ST3 B. Furthermore, instead of the processing of step ST8, it may determine whether all transmission line sets are disconnected, and unless all transmission line sets are disconnected, it may perform communication setting in step ST9 that does not use a transmission line set that is disconnected (communication setting that uses only transmission line sets that are not disconnected).

[0351] If the setting is not to use the transmission line set that is not disconnected, the control unit 202 ends the processing in step ST4. In this case, the user can replace the optical cable with another one based on the notification and change from the disconnected (disconnected state) to the connected state. On the other hand, if the setting is to use the transmission line set that is not disconnected, the control unit 202 sets the communication setting to not use the disconnected transmission line set in step ST9, and then proceeds to step ST6. Note that the communication setting not to use the disconnected transmission line set may include at least one of a setting to stop communication through the disconnected transmission line set, a setting to transfer communication signals through the disconnected transmission line set to another transmission line set that is not disconnected, etc.

[0352] Furthermore, if it is determined in the connection detection process of step ST2 that all transmission path sets are in a connected state, the control unit 202 sets communication settings according to the connection state (in this case, communication settings using all transmission path sets) in step ST5, and then performs communication processing in step ST6. Note that if a problem occurs in this communication processing, the control unit 202 stops communication of actual data in step ST7, and then returns to the connection detection process of step ST2 automatically or by user operation. If the communication processing is to be ended, the control unit 202 ends the processing in step ST4.

[0353] 32, based on the determination of a disconnection for each transmission line set, in step ST9, communication settings are made so that the disconnected transmission line set is not used. However, if the disconnection of the transmission line and the reception line in each transmission line set is determined individually, it is also possible to make communication settings so that the transmission line that is not disconnected is used.

[0354] 33 shows a first connection detection process, which is an example of the connection detection process of step ST2 in Fig. 30. This example is an example of the connection detection process in the control units 202 of the devices 200 and 200D in the optical communication systems 100A to 100D shown in Figs. 24, 26, 27, and 28 described above. In this case, as described above, optical signals are output from the transmitting units 205T of the devices 200 and 200D and sent to the device 300 side.

[0355] First, the control unit 202 starts processing in step ST11. Next, in step ST12, the control unit 202 determines whether or not an optical signal from the device A (device 200, device 200D), which is the device itself, has been received by at least one receiving unit (Rx) 205R. When a signal has been received, the control unit 202 determines in step ST13 that a disconnection has occurred, and then ends processing in step ST14. Note that disconnection may include disconnection of an optical cable, which is a connection target device fitted to device A (device 200, device 200D), or of any of the other connection target devices connected via that optical cable.

[0356] Also, in step ST12, when none of the receiving units (Rx) 205R receives an optical signal from the own device, device A (device 200, device 200D), the control unit 202 determines in step ST17 that all transmission path sets are in a connected state, in other words, determines that device 200 and device 300 are in a connected state, and then terminates the processing in step ST14.

[0357] The flowchart in Fig. 34 shows a second connection detection process, which is an example of the connection detection process of step ST2 in Figs. 30 to 32. This example is an example of the connection detection process in the control unit 202 of the device 200 in the optical communication systems 100A to 100C shown in Figs. 24, 26, and 27 described above. This example is an example of a case where the device 200 and the device 300 both transmit optical signals to each other, and where breaks in the transmitting-side transmission line and the receiving-side transmission line are not determined individually.

[0358] In this case, as described above, an optical signal is output from the transmitting unit 205T of the device 200 and sent to the device 300 side, and an optical signal is output from the transmitting unit 305T of the device 300 and sent to the device 200 side.

[0359] First, the control unit 202 starts processing in step ST11. Next, in step ST12, the control unit 202 determines whether or not an optical signal from the device A (device 200), which is its own device, has been received by at least one receiving unit (Rx) 205R. When a signal has been received, the control unit 202 determines in step ST13 that a disconnection has occurred, and then ends processing in step ST14. Note that disconnection may include disconnection of either the optical cable that is a connection target device fitted to the device A (device 200) or another connection target device connected via that optical cable.

[0360] Furthermore, in step ST12, when any of the receivers (Rx) 205R does not receive an optical signal from device A (device 200), which is the own device, the control unit 202 determines in step ST15 whether or not the receiver (Rx) 205R has received an optical signal from device B (device 300), which is the communication device to be connected. If not, the control unit 202 determines in step ST16 that the corresponding transmission path set has been disconnected, and then ends the process in step ST14.

[0361] Furthermore, in step ST12, when none of the receiving units (Rx) 205R has received an optical signal from device A (device 200), which is the device itself, and in step ST15, all of the receiving units (Rx) 205R have received an optical signal from device B (device 300), which is the communication device to be connected, the control unit 202 determines in step ST17 that all of the transmission path sets are in a connected state, in other words, that device 200 and device 300 are in a connected state, and then terminates the processing in step ST14.

[0362] In the above description, the optical signals are simply from device A (device 200) and device B (device 300), but when these optical signals are output simultaneously, it is necessary to distinguish them from each other. For example, this can be achieved by using a pilot optical signal, or by using optical signals with different wavelengths (frequencies).

[0363] The flowchart in Fig. 35 shows a third connection detection process, which is another example of the connection detection process of step ST2 in Fig. 30 to Fig. 32. This example is an example of connection detection process in the control unit 202 of the device 200 in the optical communication systems 100A to 100C shown in Fig. 24, Fig. 26, and Fig. 27 described above. This example is an example of a case where the device 200 and the device 300 both transmit optical signals to each other, and where breaks in the transmitting-side transmission line and the receiving-side transmission line are determined individually.

[0364] In this case, as described above, an optical signal is output from the transmitting unit 205T of the device 200 and sent to the device 300 side, and an optical signal is output from the transmitting unit 305T of the device 300 and sent to the device 200 side, and further, when the optical signal from the device 200 is received by the receiving unit 305R of the device 300, a reception confirmation optical signal indicating that the optical signal from the device 200 has been received is output from the transmitting unit 305T of the device 300 and sent to the device 200 side.

[0365] First, the control unit 202 starts processing in step ST21. Next, in step ST22, the control unit 202 determines whether or not an optical signal from the device A (device 200), which is its own device, has been received by at least one receiving unit (Rx) 205R. If an optical signal has been received, the control unit 202 determines in step ST23 that an optical intermediate connection device such as an optical cable or a communication device to be connected has been disconnected, and then ends processing in step ST24.

[0366] Furthermore, if in step ST22 any of the receiving units (Rx) 205R has not received an optical signal from device A (device 200), which is the own device, the control unit 202 determines in step ST25 whether or not that receiving unit (Rx) 205R has received an optical signal from device B (device 300), which is the connection target communication device. If not, the control unit 202 determines in step ST26 that at least one of the receiving side transmission line and the transmitting side transmission line in the corresponding transmission line set of the optical cable has been broken, and then ends the process in step ST24.

[0367] Furthermore, when any of the receiving units (Rx) 205R has not received an optical signal from device A (device 200), which is the own device, in step ST22, and that receiving unit (Rx) 205R has received an optical signal from device B (device 300), which is the connection target communication device, in step ST25, the control unit 202 determines in step ST27 whether or not that receiving unit (Rx) 205R has received a reception confirmation optical signal from device B (device 300) indicating that the optical signal from device A (device 200) has been received. If not, the control unit 202 determines in step ST28 that the transmission line on the transmitting side of the corresponding transmission line set has been broken, and then ends the process in step ST24.

[0368] Furthermore, in step ST22, none of the receiving units (Rx) 205R has received an optical signal from device A (device 200), which is the device itself, and in step ST25, an optical signal has been received from device B (device 300), which is the communication device to be connected. When a reception confirmation optical signal is received from device B (device 300) in step ST27, the control unit 202 determines in step ST29 that all transmission path sets are in a connected state, in other words, that device 200 and device 300 are in a connected state, and then terminates the processing in step ST24.

[0369] In the above description, the optical signals are simply from device A (device 200) and device B (device 300), but when these optical signals are output simultaneously, it is necessary to distinguish them from each other. For example, this can be achieved by using a pilot optical signal, or by using optical signals with different wavelengths (frequencies).

[0370] The flowchart in Fig. 36 shows a fourth connection detection process, which is another example of the connection detection process of step ST2 in Fig. 30 to Fig. 32. This example is an example of connection detection process in the control unit 202 of the device 200D in the optical communication system 100D in Fig. 28 described above. This example is an example of a case where the device 200D outputs an optical signal, and where breaks in the transmitting transmission line and the receiving transmission line are not determined individually.

[0371] In this case, as described above, an optical signal is output from the transmitting section 205T of the device 200D and sent to the device 300 side.

[0372] First, the control unit 202 starts processing in step ST31. Next, in step ST32, the control unit 202 determines whether or not an optical signal from the device A (device 200D), which is its own device, has been received by at least one receiving unit (Rx) 205R. When a signal has been received, the control unit 202 determines in step ST33 that a detachment has occurred, and then ends processing in step ST34. Note that detachment may include detachment of either the optical cable, which is a connection target device fitted to the device A (device 200D), or another connection target device connected via that optical cable.

[0373] Furthermore, in step ST32, when any of the receiving units (Rx) 205R has not received an optical signal from the device A (device 200D), which is the device itself, the control unit 202 determines in step ST35 whether or not the corresponding receiving unit (rx) 205r has received an optical signal from the device A (device 200D), which is the device itself. If an optical signal has been received, the control unit 202 determines in step ST36 that there is a break in the optical cable or in the corresponding transmission path set of the internal transmission path between the circulator 208 of device A (device 200D) and the receptacle 201, and then ends the process in step ST34.

[0374] Furthermore, in step ST32, when none of the receiving units (Rx) 205R has received an optical signal from the device A (device 200D), which is the device itself, and in step ST35, none of the receiving units (rx) 205r has received an optical signal from the device A (device 200D), which is the device itself, the control unit 202 determines in step ST37 that all of the transmission path sets are in a connected state, in other words, that the device 200D and the device 300 are in a connected state, and then terminates the processing in step ST34.

[0375] In the above description, the optical signal is simply from device A (device 200D), which is the device itself, but for example, in a case where device B (device 300) is configured to be able to perform the same connection detection process as device A (device 200D), an optical signal is transmitted from device B (device 300) to device A (device 200D), and optical signals from both devices are output simultaneously, it is necessary to make them distinguishable from each other. For example, this can be achieved by using a pilot optical signal, or optical signals with different wavelengths (frequencies), etc.

[0376] The flowchart in Fig. 37 shows a fifth connection detection process, which is another example of the connection detection process of step ST2 in Fig. 30 to Fig. 32. This example is an example of the connection detection process in the control unit 202 of the device 200D in the optical communication system 100D in Fig. 28 described above. This example is an example of the case where the device 200D is applied to an optical communication system in which an optical signal is output, and where breaks in the transmitting-side transmission line and the receiving-side transmission line are individually determined.

[0377] In this case, as described above, an optical signal is output from the transmitting unit 205T of the device 200D and sent to the device 300 side, and when the optical signal from the device 200 is received by the receiving unit 305R of the device 300, a reception confirmation optical signal indicating that the optical signal from the device 200 has been received is output from the transmitting unit 305T of the device 300 and sent to the device 200 side.

[0378] First, the control unit 202 starts processing in step ST41. Next, in step ST42, the control unit 202 determines whether or not an optical signal from the device A (device 200D), which is its own device, has been received by at least one receiving unit (Rx) 205R. If an optical signal has been received, the control unit 202 determines in step ST43 that either an optical intermediate connection device such as an optical cable or a target communication device B has been disconnected, and then ends processing in step ST44.

[0379] Furthermore, in step ST42, when any of the receiving units (Rx) 205R has not received an optical signal from the device A (device 200D), which is the device itself, the control unit 202 determines in step ST45 whether or not the corresponding receiving unit (rx) 205r has received an optical signal from the device A (device 200D), which is the device itself. If an optical signal has been received, the control unit 202 determines in step ST46 that the transmission line on the transmitting side in the corresponding transmission line set has been broken, and then ends the process in step ST44.

[0380] Furthermore, if any of the receiving units (Rx) 205R does not receive an optical signal from the device A (device 200D), which is the device itself, in step ST42, and if the corresponding receiving unit (rx) 205r does not receive an optical signal from the device A (device 200D), which is the device itself, in step ST45 (thus, the transmission line on the transmission line is not broken), the control unit 202 determines in step ST47 whether or not the receiving unit (Rx) 205R has received a reception confirmation optical signal from the device B (device 300), which is the communication device to be connected, indicating that the optical signal from the device A (device 200D) has been received. If not, the control unit 202 determines in step ST48 that the reception line on the transmission line set on the optical cable is broken, and then ends the process in step ST44.

[0381] Furthermore, in step ST42, when none of the receiving units (Rx) 205R has received an optical signal from the own device, device A (device 200D), in step ST45, none of the receiving units (rx) 205r has received an optical signal from the own device, device A (device 200D), in step ST47, when all of the receiving units (Rx) 205R have received a reception confirmation optical signal from device B (device 300), the control unit 202 determines in step ST49 that all of the transmission path sets are in a connected state, in other words, that device 200D and device 300 are in a connected state, and then terminates the processing in step ST44.

[0382] In the above description, the optical signal is simply from device A (device 200D), which is the device itself, but for example, in a case where device B (device 300) is configured to be able to perform the same connection detection process as device A (device 200D), an optical signal is transmitted from device B (device 300) to device A (device 200D), and optical signals from both devices are output simultaneously, it is necessary to make them distinguishable from each other. For example, this can be achieved by using a pilot optical signal, or optical signals with different wavelengths (frequencies), etc.

[0383] The flowchart in Fig. 38 shows a sixth connection detection process, which is an example of the connection detection process of step ST2 in Fig. 30 to Fig. 32. This example is an example of the connection detection process in the control unit 202 of the device 200E in the optical communication system 100E shown in Fig. 29 above. In this case, as described above, an optical signal is output from the device 200E and sent to the device 300E.

[0384] First, the control unit 202 starts processing in step ST51. Next, in step ST52, the control unit 202 determines whether or not an optical signal from the device A (device 200E), which is its own device, has been received by at least one receiving unit (rx) 205r. When a signal has been received, the control unit 202 determines in step ST53 that a detachment has occurred, and then ends processing in step ST54. Note that detachment may include detachment of either the optical cable, which is a connection target device fitted to the device A (device 200E), or any of the other connection target devices connected via that optical cable.

[0385] Also, in step ST52, when none of the receiving units (rx) 205r receives an optical signal from the own device, device A (device 200E), the control unit 202 determines in step ST57 that all transmission path sets are in a connected state, in other words, determines that device 200E and device 300E are in a connected state, and then terminates the processing in step ST54.

[0386] The flowchart in Fig. 39 shows a seventh connection detection process, which is another example of the connection detection process of step ST2 in Fig. 30 to Fig. 32. This example is an example of connection detection process in the control unit 202 of the device 200E in the optical communication system 100E in Fig. 20 described above. This example is an example of a case where the present invention is applied to an optical communication system provided with a dedicated detection transmission line, and where breaks in the transmitting side transmission line and the receiving side transmission line are not determined individually.

[0387] In this case, as described above, an optical signal (which does not need to be identifiable as an optical signal from device 200E) is output from transmitting unit 205T of device 200E and sent to device 300E, and an optical signal (which does not need to be identifiable as an optical signal from device 300E) is output from transmitting unit 305T of device 300E and sent to device 200E.

[0388] First, the control unit 202 starts processing in step ST51. Next, in step ST52, the control unit 202 determines whether or not an optical signal from device A (device 200E) has been received by at least one receiving unit (rx) 205r. If an optical signal has been received, the control unit 202 determines in step ST53 that any optical intermediate connection device such as an optical cable or a communication device to be connected has been disconnected, and then ends processing in step ST54.

[0389] Furthermore, in step ST52, when an optical signal is not received by any of the receiving units (rx) 205r, the control unit 202 determines in step ST55 whether or not an optical signal from the device B (device 300E) is received by the corresponding receiving unit (Rx) 205R. If an optical signal is not received, the control unit 202 determines in step ST56 that the corresponding transmission path set is disconnected, and then ends the process in step ST54.

[0390] Furthermore, in step ST52, when none of the receiving units (rx) 205r receives an optical signal from device A (device 200E), and in step ST55, all of the receiving units (Rx) 205R receive an optical signal from device A (device 200E), the control unit 202 determines in step ST57 that all of the transmission path sets are in a connected state, in other words, that device 200E and device 30E are in a connected state, and then terminates the processing in step ST54.

[0391] The flowchart in Fig. 40 shows an eighth connection detection process, which is another example of the connection detection process of step ST2 in Fig. 30 to Fig. 32. This example is an example of connection detection process in the control unit 202 of the device 200E in the optical communication system 100E in Fig. 29 described above. This example is an example of a case where the present invention is applied to an optical communication system provided with a dedicated detection transmission line, and is an example of a case where breaks in the transmitting side transmission line and the receiving side transmission line are determined individually.

[0392] In this case, as described above, an optical signal (which does not need to be identifiable as an optical signal from device 200E) is output from transmitting unit 205T of device 200E and sent to device 300E, and an optical signal (which does not need to be identifiable as an optical signal from device 300E) is output from transmitting unit 305T of device 300E and sent to device 200E, and further, when receiving unit 305R of device 300E receives an optical signal from device A (device 200E), a reception confirmation optical signal indicating that the optical signal has been received is output from transmitting unit 305T of device 300E and sent to device 200E.

[0393] First, the control unit 202 starts processing in step ST61. Next, in step ST62, the control unit 202 determines whether or not an optical signal from device A (device 200E) has been received by at least one receiving unit (rx) 205r. If a signal has been received, the control unit 202 determines in step ST63 that an optical intermediate connection device such as an optical cable or device B (the connection target communication device) has been disconnected, and then ends processing in step ST64.

[0394] Furthermore, in step ST62, when any of the receiving units (rx) 205r has not received an optical signal from device A (device 200E), the control unit 202 determines in step ST65 whether or not the corresponding receiving unit (Rx) 205R has received an optical signal from device B (device 300E). If not, the control unit 202 determines in step ST66 that at least one of the receiving side transmission line and the transmitting side transmission line in the corresponding transmission line set has been broken, and then ends the process in step ST64.

[0395] Furthermore, when any of the receiving units (rx) 205r has not received an optical signal from device A (device 200E) in step ST62, and the corresponding receiving unit (Rx) 205R has received an optical signal from device B (device 300E) in step ST65, the control unit 202 determines in step ST67 whether or not that receiving unit (Rx) 205R has received a reception confirmation optical signal from device B (device 300E), which is the target communication device, indicating that the optical signal from device A (device 200E) has been received. If not, the control unit 202 determines in step ST68 that the transmission line on the transmitting side of the corresponding transmission line set has been broken, and then ends the process in step ST64.

[0396] Furthermore, in step ST62, when none of the receiving units (rx) 205r have received an optical signal from device A (device 200E), and in step ST65, all of the receiving units (Rx) 205R have received an optical signal from device B (device 300E), and in step ST67, all of the receiving units (Rx) 205R have received a reception confirmation optical signal from device B (device 300E), the control unit 202 determines in step ST69 that all of the transmission path sets are in a connected state, in other words, that device 200E and device 300E are in a connected state, and then terminates the processing in step ST64.

[0397] 1-3-2. Communication Processing The flowchart in FIG. 41 shows an example of the communication processing in step ST6 in FIGS.

[0398] First, the control unit 202 starts processing in step ST71. Next, the control unit 202 starts communication of actual data in step ST72. In this case, in each transmission path set (communication channel), the transmitter 205T starts transmitting a communication optical signal (transmission optical signal) of actual data to the target communication device via the transmission side transmission path, and the receiver 205R starts receiving a communication optical signal (reception optical signal) of actual data from the target communication device via the reception side transmission path.

[0399] Next, in step ST73, the control unit 202 determines whether a problem has occurred. For example, the control unit 202 determines that a problem has occurred when the receiving unit 205 in any of the transmission path sets no longer receives a communication optical signal (received optical signal). If it determines that a problem has occurred, the control unit 202 proceeds to the processing of step ST7 in FIGS. 30 to 32.

[0400] If no problem occurs in step ST73, the control unit 202 determines whether or not communication has ended in step ST75. For example, the control unit 202 determines that communication has ended when the user performs an operation to end communication. If communication has not ended, the control unit 202 returns to the processing of step ST73.

[0401] If the communication is to be ended in step ST75, the control section 202 ends the communication in step ST76, and then ends the process in step ST77.

[0402] "1-4. Identifying the Detachment Position" Next, the identification of the detachment position (detachment point) will be described. The detachment position is identified, for example, automatically when detachment is detected, or when a user instructs identification of the detachment point via a UI (User Interface) when detachment is detected. Possible methods for identifying the detachment position include (1) using pulsed light and identifying the detachment position from the delay time of returned light, (2) using continuous light and identifying the detachment position from the delay time of returned light, and (3) identifying the detachment position using an identifier (ID) unique to the other end connector held by the connected target device.

[0403] "1-4-1. Using pulsed light (optical signal) to identify the departure position from the delay time of the returned light" First, we will explain the above-mentioned method (1), that is, the method of using pulsed light (optical signal) to identify the departure position from the delay time of the returned light (hereinafter referred to as "first method" where appropriate). This first method is a distance measurement method known as dToF (direct Time-of-Flight).

[0404] Fig. 42 shows an example of a specific configuration for realizing the first technique. In Fig. 42, parts corresponding to those in Fig. 27 are given the same reference numerals, and detailed descriptions thereof will be omitted where appropriate. In the example shown, separation occurs at plug 403-3 of optical cable 400-3, but the separation location is not limited to this and may be at any location in the optical intermediate connector or the communication device to be connected.

[0405] In order to identify the separation position, the device 200 uses at least one transmission line set, for example, a transmitter 205T and a receiver 205R corresponding to the first transmission line set. When identifying the separation position, a pulsed optical signal is transmitted from the transmitter 205T. At this time, the pulsed optical signal is output from the receptacle 201 and transmitted through the transmitting-side optical cable main transmission line 401-3T of the optical cable 400-3. This pulsed optical signal is reflected by the plug 403-3 of the optical cable 400-3, and the pulsed optical signal as reflected light is returned through the receiving-side optical cable main transmission line 401-3R of the optical cable 400-3. This returned pulsed optical signal is input to the receptacle 201 and received by the receiver 205R.

[0406] The signal processing unit 204 then performs a process of measuring the time from when a pulsed optical signal is output from the transmitter 205T to when the pulsed optical signal is input to the receiver 205R, and the control unit 202 determines the distance to the separation position based on the measurement result. The separation point may also be determined based on the distance to the separation position. The separation position information indicating the separation position, which is composed of the distance and the separation point, constitutes connection relationship information that is detected when the connection state between the receptacle 201 of the device 200 and the receptacle 301 of the device 300 (the device 300 is not shown in FIG. 42 ), is at least optically disconnected, similar to the above-described separation and disconnection. The separation position determined in this manner is displayed on a display, such as the presentation unit 206, allowing the user to easily grasp the separation position.

[0407] The flowchart in Figure 43 shows an example of a processing procedure for identifying a separation position. First, the control unit 202 starts processing in step ST101. Next, the control unit 202 causes the transmitter 205T to transmit a pulsed optical signal in step ST102. Next, the control unit 202 causes the receiver 205R to receive the pulsed optical signal as reflected light in step ST103. Next, the control unit 202 causes the signal processor 204 to process the signal processor 204 to identify the separation position in step ST104. Thereafter, the control unit 202 ends processing in step ST105.

[0408] It should be noted that the specific configuration shown in Fig. 42 is applied to the optical communication system 100C in Fig. 27, but it is needless to say that it can be similarly applied to the optical communication system 100A shown in Fig. 24, the optical communication system 100B shown in Fig. 26, the optical communication system 100D shown in Fig. 28, and the optical communication system 100E shown in Fig. 29. Here, only in the case of the optical communication system 100E shown in Fig. 29, the returned pulsed optical signal is input to the receiving unit 205r, not to the receiving unit 205R.

[0409] "1-4-2. Using continuous light (optical signal) to identify the departure position from the delay time of the returned light" Next, we will explain the above-mentioned method (2), that is, a method of using continuous light (optical signal) to identify the departure position from the delay time of the returned light (hereinafter referred to as the "second method" as appropriate). This second method is a distance measurement method known as FMCW (Frequency Modulated Continuous Wave).

[0410] Figure 44 shows an example of a specific configuration for implementing the second technique. In this Figure, parts corresponding to those in Figure 27 are given the same reference numerals, and detailed descriptions thereof will be omitted where appropriate. In the example shown, separation occurs at plug 403-3 of optical cable 400-3, but the separation location is not limited to this and may be at any location in the optical intermediate connector or the communication device to be connected.

[0411] In order to identify the separation position, the device 200 uses one transmission line set, for example, a transmitter 205T and a receiver 205R corresponding to the first transmission line set. The device (device A) 200 further includes optical switches 211 to 214, a demultiplexer 215, and a multiplexer 216.

[0412] The output side of transmitter 205T is connected to a movable terminal of optical switch 211. A fixed terminal on the a side of optical switch 211 is connected to the input side of demultiplexer 215, and one output side of demultiplexer 215 is connected to a fixed terminal on the a side of optical switch 212. A fixed terminal on the b side of optical switch 211 is connected to a fixed terminal on the b side of optical switch 212. The movable terminal of optical switch 212 is connected to receptacle 201.

[0413] The input side of receiving unit 205R is connected to a movable terminal of optical switch 213. A fixed terminal on the a side of optical switch 213 is connected to the output side of multiplexer 216, one input side of multiplexer 216 is connected to the other output side of demultiplexer 215, and the other input side of multiplexer 216 is connected to a fixed terminal on the a side of optical switch 214. A fixed terminal on the b side of optical switch 213 is connected to a fixed terminal on the b side of optical switch 214. The movable terminal of optical switch 214 is connected to receptacle 201. Optical switches 211 to 214 are normally connected to their b sides, but are connected to their a sides when specifying the separation position.

[0414] When identifying the separation position, a chirp optical signal, i.e., a continuous sinusoidal optical signal whose frequency increases over time, is output from the transmitter 205T. This chirp optical signal is input to and demultiplexed by the demultiplexer 215, and the demultiplexed chirp optical signals are output from one and the other output sides of the demultiplexer 215.

[0415] The chirp optical signal output from the other output side of the demultiplexer 215 is input to one input side of the multiplexer 216. The chirp optical signal output from one output side of the demultiplexer 215 is also output from the receptacle 201 and transmitted via the transmitting side optical cable main transmission line 401-3T of the optical cable 400-3. This chirp optical signal is reflected by the plug 403-3 of the optical cable 400-3, and the chirp optical signal as reflected light is returned via the receiving side optical cable main transmission line 401-3R of the optical cable 400-3. This returned chirp optical signal is input to the receptacle 201 and sent to the other input side of the multiplexer 216.

[0416] The multiplexer 216 combines the transmitted chirp signal (the chirp signal from the demultiplexer 215) and the received chirp signal (the returned chirp signal) to generate an intermediate frequency (IF) optical signal having a frequency (beat frequency) that is the difference between the transmitted and received frequencies. The IF optical signal output from the output side of the multiplexer 216 is sent to the receiver 205R.

[0417] Then, the signal processing unit 204 performs processing to measure the frequency (beat frequency) of the IF optical signal input to the receiving unit 205R, and the control unit 202 identifies the distance to the separation position based on the measurement results. The separation location may also be identified based on the distance to the separation position. The separation position, which is composed of the distance and separation location, constitutes connection relationship information that is detected when the connection state between the receptacle 201 of the device 200 and the receptacle 301 of the device 300 (the device 300 is not shown in FIG. 44 ), is at least optically disconnected, similar to the above-described separation and disconnection. The separation position identified in this manner is displayed on a display, such as the presentation unit 206, allowing the user to easily grasp the separation position.

[0418] The configuration example shown in Figure 44 is applied to the optical communication system 100C in Figure 27, but it can of course also be applied to the optical communication system 100A shown in Figure 24, the optical communication system 100B shown in Figure 26, the optical communication system 100D shown in Figure 28, and the optical communication system 100E shown in Figure 29.

[0419] The flowchart in Figure 45 shows an example of the processing procedure when identifying the separation position. First, the control unit 202 starts the processing in step ST111. Next, the control unit 202 switches to the measurement side optical path in step ST112. In this case, the optical switches 211 to 214 are switched to connect to side a.

[0420] Next, in step ST113, the control unit 202 causes the transmitter 205T to transmit a chirp optical signal. Next, in step ST114, the control unit 202 causes the receiver 205R to receive the IF optical signal. Next, in step ST115, the control unit 202 causes the signal processor 204 to identify the separation position through processing. Next, in step ST116, the control unit 202 switches to the optical path on the communication side. In this case, the optical switches 211 to 214 are switched so as to be connected to side b. Thereafter, the control unit 202 ends the processing in step ST117.

[0421] Figure 46 shows another example of a specific configuration for realizing the second technique. In Figure 46, parts corresponding to those in Figures 27 and 44 are given the same reference numerals, and detailed descriptions thereof will be omitted where appropriate. In the example shown, the detachment occurs at plug 403-3 of optical cable 400-3, but the detachment location is not limited to this and may be at any location in the optical intermediate connector or the communication device to be connected. The configuration example shown in Figure 44 above was an example of a configuration in which communication and measurement are performed separately, but the configuration example shown in Figure 46 is an example of a configuration in which measurement can be performed while communication is ongoing, and measurement is performed at wavelengths not used for communication using wavelength multiplexing.

[0422] In the device 200, similar to the configuration example of Fig. 44, one transmission line set, for example, a transmitter 205T and a receiver 205R corresponding to the first transmission line set, are used to identify the separation position. Furthermore, while the device (device A) 200 in the configuration example of Fig. 44 was provided with optical switches 211 to 214, the configuration example of Fig. 46 is provided with a measurement transmitter 221, a measurement receiver 223, and WDM couplers (Wavelength Division Multiplexing Couplers) 222 and 224. Here, the WDM couplers are conventionally well-known elements that function as demultiplexers and multiplexers in wavelength multiplexing systems, and will not be described in detail.

[0423] The output side of communication transmitter 205T is connected to port 4 of WDM coupler 222. The output side of measurement transmitter 221 is connected to the input side of splitter 215, one output side of splitter 215 is connected to port 3 of WDM coupler 222, and the other output side of splitter 215 is connected to one input side of multiplexer 216. Port 1 of WDM coupler 222 is connected to receptacle 201.

[0424] The input side of communication receiver 205R is connected to port 4 of WDM coupler 224. The input side of measurement receiver 223 is connected to the output side of multiplexer 216, and the other input side of multiplexer 216 is connected to port 3 of WDM coupler 224. Port 1 of WDM coupler 224 is connected to receptacle 201.

[0425] When identifying the separation position, a chirped optical signal of a measurement wavelength, i.e., a continuous sinusoidal optical signal whose frequency increases over time, is output from the measurement transmitter 221. This chirped optical signal is input to and branched by the branching filter 215, and the branched chirped optical signals are output from one and the other output sides of the branching filter 215.

[0426] The chirp optical signal output from the other output side of demultiplexer 215 is input to one input side of multiplexer 216. The chirp optical signal output from one output side of demultiplexer 215 is output from receptacle 201 via port 3 → port 1 of WDM coupler 222 and transmitted via transmitting side optical cable main transmission line 401-3T of optical cable 400-3. This chirp optical signal is reflected by plug 403-3 of optical cable 400-3, and the chirp optical signal as reflected light is returned via receiving side optical cable main transmission line 401-3R of optical cable 400-3. This returned chirp optical signal is input to receptacle 201 and sent to the other input side of multiplexer 216 via port 1 → port 3 of WDM coupler 224.

[0427] The multiplexer 216 combines the transmitted chirp signal (the chirp signal from the demultiplexer 215) and the received chirp signal (the returned chirp signal) to generate an IF optical signal having a frequency (beat frequency) that is the difference between the transmitted and received chirp signals. The IF optical signal output from the output side of the multiplexer 216 is sent to the receiver 223 for measurement.

[0428] The signal processing unit 204 then performs processing to measure the frequency (beat frequency) of the IF optical signal input to the receiving unit 223, and the control unit 202 identifies the distance to the separation position based on the measurement results. The separation location may also be identified based on the distance to the separation position. The separation position, which is composed of the distance and separation location, constitutes connection relationship information that is detected when the connection state between the receptacle 201 of the device 200 and the receptacle 301 of the device 300 (the device 300 is not shown in FIG. 46 ), similar to the above-described separation and disconnection, is at least optically disconnected. The separation position identified in this manner is displayed on a display, such as the presentation unit 206, allowing the user to easily grasp the separation position.

[0429] During communication, an optical signal with a communication wavelength is output from the communication transmitter 205T. This optical signal is output from the receptacle 201 via port 4→port 1 of the WDM coupler 222 and transmitted via the transmitting-side optical cable main transmission path 401-3T of the optical cable 400-3. An optical signal with a communication wavelength transmitted via the receiving-side optical cable main transmission path 401-3R of the optical cable 400-3 is input to the receptacle 201 and sent to the communication receiver 205R via port 1→port 4 of the WDM coupler 224.

[0430] The configuration example shown in Figure 46 is applied to the optical communication system 100C of Figure 27, but it is of course possible to apply it to the optical communication system 100A shown in Figure 24, the optical communication system 100B shown in Figure 26, the optical communication system 100D shown in Figure 28, and the optical communication system 100E shown in Figure 29, just like the configuration example shown in Figure 44 above.

[0431] Furthermore, although t...

Claims

1. An optical connector, comprising: a housing; a bending portion configured to bend one or more transmitted lights input from one or more transmitted-side connector external transmission paths located on one end side of the housing and emit the one or more transmitted lights into a space formed within the housing; and a reflecting portion provided within the housing and configured to reflect the one or more transmitted lights emitted into the space from the bending portion, wherein a bending angle of the bending portion is set to an angle at which the one or more transmitted lights are transmitted toward the reflecting portion, and a reflection angle of the reflecting portion is set to an angle at which the one or more transmitted lights are located on the one end side of the housing via the bending portion and are respectively transmitted toward one or more received-side connector external transmission paths paired with the one or more transmitted-side connector external transmission paths.

2. The optical connector according to claim 1, wherein when no other optical connector is fitted to the other end side of the housing, a non-fitting optical path for transmitting the one or more transmitted lights toward the received-side connector external transmission path is constructed, and when the other optical connector is fitted to the other end side of the housing, a fitting optical path for transmitting the one or more transmitted lights from the other end side toward the other optical connector and for transmitting one or more received lights from the other optical connector toward the received-side connector external transmission path is constructed in cooperation with the other optical connector.

3. The optical connector according to claim 1, further comprising: a plurality of transmitted-side connector internal transmission paths configured to transmit the plurality of transmitted lights input from the plurality of transmitted-side connector external transmission paths; and a plurality of received-side connector internal transmission paths respectively paired with any one of the plurality of transmitted-side connector internal transmission paths, wherein each optical connector internal transmission path set is constituted by the paired transmitted-side connector internal transmission path and received-side connector internal transmission path.

4. The optical connector according to claim 3, wherein each optical connector internal transmission path set is paired according to a correspondence relationship corresponding to an identifier of the optical connector.

5. The optical connector according to claim 1, wherein the reflecting portion is constituted by one or more reflecting surfaces, and the bending portion is constituted by a prism or a reflecting surface.

6. The optical connector according to claim 1, wherein the received-side connector external transmission path is a detection-only transmission path not used for actual data communication.

7. A optical communication device comprising a housing, a bending portion that bends one or more transmitted lights input from one or more transmission-side device internal transmission paths located on one end side of the housing and emits the one or more transmitted lights into a space formed within the housing, and a reflection portion provided within the housing that reflects the one or more transmitted lights emitted into the space from the bending portion, wherein a bending angle of the bending portion is set to an angle at which the one or more transmitted lights are transmitted toward the reflection portion, a reflection angle of the reflection portion is set to an angle at which the one or more transmitted lights are located on the one end side of the housing via the bending portion and are transmitted toward one or more reception-side device internal transmission paths respectively paired with the one or more transmission-side device internal transmission paths, the optical connector of the own device, one or more transmission portions that transmit the transmitted lights to the one or more transmission-side device internal transmission paths respectively, one or more reception portions that receive the one or more transmitted lights transmitted via the one or more reception-side device internal transmission paths as one or more detection reception lights, and a control portion that detects connection relation information based on a reception state of the one or more detection reception lights in the one or more reception portions.

8. The optical communication device according to claim 7, wherein the reception state is a state based on a connection relation between the optical connector of the own device and an optical connector of a communication device to be connected of the connection target communication device.

9. In a non-fitting state in which no other optical connector is fitted to the other end side of the housing, a non-fitting optical path for transmitting the one or more transmitted lights transmitted from the one or more transmission portions toward the reception-side device internal transmission paths is constructed, the one or more reception portions receive the one or more transmitted lights as the one or more detection reception lights, and in a fitting state in which the other optical connector is fitted to the other end side of the housing, a fitting optical path for transmitting the one or more transmitted lights transmitted from the one or more transmission portions toward the other optical connector from the other end side is constructed in cooperation with the other optical connector. The optical communication device according to claim 7 is configured as such.

10. The optical communication device according to claim 9, wherein one or more lights input from the other optical connector to the optical connector of the own device via the fitting optical path are transmitted toward the reception-side device internal transmission paths.

11. The optical connector of the own device is configured to be connectable to an optical cable of one of the optical intermediate connection devices via one or more optical intermediate connection devices including at least one optical cable, and a communication device optical connector to be connected, which is configured to be mechanically and optically connectable. The optical communication device according to claim 7.

12. The one or more optical intermediate connection devices are each provided with an intermediate connection device optical connector on one end side and the other end side. When a non-fitting optical path is constructed in any of the optical connector of the own device or the intermediate connection device optical connector provided on the other end side of the one or more optical intermediate connection devices, the control unit is based on the reception state of the detection reception light, which is the light in which the transmission light is returned by the non-fitting optical path, at the one or more reception units, and detects the connection relationship information. The optical communication device according to claim 11.

13. The optical connector of the own device is configured to be indirectly connectable to a communication device optical connector to be connected via an optical intermediate connection device including at least one optical cable. The optical communication device according to claim 7.

14. The connection relationship information is disconnection information indicating disconnection between two optical connectors that should be fitted among a plurality of optical connectors between the optical connector of the own device and the communication device optical connector to be connected. The optical communication device according to claim 7.

15. The connection relationship information is disconnection position information indicating the position of the disconnection. The optical communication device according to claim 14.

16. Any one of the one or more reception units is paired with any one of the one or more transmission units, and each transmission / reception unit set is configured by the paired transmission unit and reception unit. The control unit detects the connection relationship information for each transmission / reception unit set. The optical communication device according to claim 7.

17. The control unit detects, as the connection relationship information, path information indicating which reception unit among the plurality of reception units each of the plurality of transmission lights transmitted from each of the plurality of transmission units is received by. The optical communication device according to claim 7.

18. The control unit detects, as the connection relationship information, identifier information for identifying a connector in a connection state immediately before the disconnection position based on the path information. The optical communication device according to claim 17.

19. The optical communication device according to claim 17, wherein the control unit detects, as the connection relationship information, disconnection position information indicating a disconnection position based on the path information.

20. The optical communication device according to claim 7, wherein the connection relationship information is disconnection information indicating a disconnection between the one or more transmission units and the connection target communication device optical connector.

21. One or more optical cable inner transmission path sets each comprising one or more transmission side optical cable inner transmission paths and one or more reception side optical cable inner transmission paths paired with each of the one or more transmission side optical cable inner transmission paths; a first optical connector provided at one end side of the one or more optical cable inner transmission path sets; and a second optical connector provided at the other end side of the one or more optical cable inner transmission path sets, wherein the second optical connector includes a housing; a bending portion that bends one or more transmission lights input from one or more transmission side optical cable outer transmission paths located at one end side of the housing to the first optical connector and received via the transmission side optical cable inner transmission path, and emits the lights into a space formed in the housing; and a reflection portion provided in the housing and configured to reflect the one or more transmission lights emitted into the space from the bending portion, wherein a bending angle of the bending portion is set to an angle at which the one or more transmission lights are transmitted toward the reflection portion, and a reflection angle of the reflection portion is set to an angle at which the one or more transmission lights are transmitted toward one or more reception side optical cable outer transmission paths that are located at the one end side of the housing via the bending portion and are paired with the one or more transmission side optical cable outer transmission paths, respectively.

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