Optical communication system and optical power supply method

Abstract

To provide an optical communication system and a method for optical power supply which can operate a node set in a network even if there is a breakage in the network.SOLUTION: An optical communication system 10 in a ring-shaped network 11 includes: a parent node 12 for executing the output of a first laser beam 15A to a first direction path 14A in the network 11 and the output of a second laser beam 15B to a second direction path 14B in the network 11 in a switchable manner; and a plurality of child nodes 13 which are operated by the optical power supply from one of the first laser beam 15A and the second laser beam 15B. The first laser beam 15A and the second laser beam 15B have different wavelengths. A first laser beam 15A and the second laser beam 15B propagating from the parent node 12 to each child node 13 travel in different directions.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to an optical communication system and an optical power supply method. [Background technology]

[0002] In order to respond to changes in the usage environment of optical fiber networks, construction work such as changing the direction of optical fiber and installing additional optical fiber is carried out with a certain frequency. This work used to be carried out by construction workers who went to the site, but in recent years, technology has been proposed to carry out such work by remote control (see Non-Patent Document 1 and Non-Patent Document 2). [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] R. Helkey ​​et.al., “Remotely powered optical switch for remote subscriber aggregation and OTDR measurement in PON”, 33rd European Conference and Exhibition of Optical Communication (2007) [Non-patent document 2] Tomohiro Kawano, Tetsuya Manabe, Akihiro Kuroda, Kazuhide Nakae, Hiroshi Watanabe, Kazunori Katayama, "A Study on Serial Connection Method of Remote Optical Path Switching Nodes", IEICE General Conference 2022, B-13-28 Summary of the Invention [Problem to be solved by the invention]

[0004] The networks described in Non-Patent Documents 1 and 2 include a control device and one or more nodes. The control device and the multiple nodes are connected via a path formed by a single optical fiber. In other words, the control device, the multiple nodes, and the path connecting them form a bus network. The control device optically supplies power to each node via the bus network and performs optical communication with each node. This controls the operation of each node.

[0005] If a single optical fiber in a bus-type network is broken, the nodes in the network will be unable to carry out optical communications to transmit control signals, etc. As a result, the nodes will no longer be able to perform their assigned functions. Furthermore, if the optical communications are accompanied by optical power supply to the nodes, the nodes will lose power.

[0006] The present disclosure has been made in consideration of the above-mentioned circumstances, and aims to provide an optical communication system and an optical power supply method that are capable of operating nodes installed in a network even if a disconnection occurs in the network. [Means for solving the problem]

[0007] An optical communication system according to one embodiment of the present disclosure comprises a parent node that switchably outputs a first laser light to a first path in a ring-type network and a second laser light to a second path in the network, and a plurality of child nodes that operate using optical power supplied from the first laser light or the second laser light, wherein the wavelengths of the first laser light and the second laser light are different from each other, and the directions of travel of the first laser light and the second laser light from the parent node toward each of the child nodes are different from each other.

[0008] An optical power supply method according to one embodiment of the present disclosure switchably outputs a first laser beam from a parent node to a plurality of child nodes via a first route of the network and a second laser beam from the parent node to each of the child nodes via a second route of the network in a ring-type network, and converts the first laser beam or the second laser beam into electric power at each of the child nodes, the first laser beam and the second laser beam having different wavelengths, and the first laser beam and the second laser beam traveling from the parent node to each of the child nodes having different directions. [Effects of the Invention]

[0009] According to the present disclosure, it is possible to provide an optical communication system and an optical power supply method that are capable of operating nodes installed in a network even if a disconnection occurs in the network. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram of an optical communication system according to an embodiment of the present disclosure. [Figure 2A] FIG. 2A is a diagram for explaining an example of the operation of the optical communication system. [Figure 2B] FIG. 2B is a diagram for explaining an example of the operation of the optical communication system. [Figure 3] FIG. 3 is a diagram showing a first example of a specific configuration of a parent node and a child node. [Figure 4] FIG. 4 is a diagram showing a second example of a specific configuration of a parent node and a child node. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an optical communication system and an optical power supply method according to an embodiment of the present disclosure will be described. Note that common parts in the drawings are denoted by the same reference numerals, and duplicated explanations will be omitted.

[0012] First, an overview of the optical communication system 10 will be described. Fig. 1 is a schematic diagram of an optical communication system 10 according to an embodiment of the present disclosure. As shown in Fig. 1, the optical communication system 10 includes a parent node (in-station node) 12 and multiple child nodes (out-station nodes) 13 provided in a network 11. For convenience of explanation, Fig. 1 shows four child nodes 13A, 13B, 13C, and 13D. However, the number of child nodes 13 is not limited to four and may be set appropriately depending on the scale and use of the network 11.

[0013] The network 11 is constructed by a first path 14A and a second path 14B, which are optical transmission paths between a parent node 12 and each child node 13. The first path 14A and the second path 14B pass through a plurality of child nodes 13 in order to form a so-called ring-type network. The plurality of optical fibers that make up the first path 14A and the second path 14B are bundled and laid along a predetermined route between the child nodes 13, for example, as a single optical cable (not shown).

[0014] Parent node 12 is installed in a relatively large-scale communication facility such as a communications carrier's accommodation station or relay station, and operates on external power such as a commercial power source. Parent node 12 outputs first laser light 15A to first path 14A. Parent node 12 also outputs second laser light 15B to second path 14B. Both first laser light 15A and second laser light 15B are used for optical communication with child node 13 and optical power supply to child node 13.

[0015] Parent node 12 switches between outputting first laser light 15A and outputting second laser light 15B. For example, parent node 12 alternately switches between outputting first laser light 15A to first path 14A and outputting second laser light 15B to second path 14B. This switching may be performed based on a preset cycle, or may be performed after detecting a disconnection in network 11. Parent node 12 can also output both first laser light 15A and second laser light 15B. Outputting both first laser light 15A and second laser light 15B is performed, for example, after detecting a disconnection in network 11.

[0016] As shown in Fig. 1, the directions of travel of first laser light 15A and second laser light 15B traveling from parent node 12 to each child node 13 are set to be different from each other. That is, these two traveling directions are opposite to each other. For example, as shown in Fig. 1, first laser light 15A enters one end of network 11 from parent node 12 and travels clockwise along first path 14A. Meanwhile, second laser light 15B enters the other end of network 11 from parent node 12 and travels counterclockwise along second path 14B.

[0017] The first laser light 15A and the second laser light 15B have different wavelengths. However, despite the different wavelengths, both the first laser light 15A and the second laser light 15B have sufficient intensity (energy) to optically power each child node 13. Furthermore, in order to communicate with the child node 13, each laser light may be on / off modulated by a modulator (first modulator 22 or second modulator 27 (see FIG. 3) described later). The on / off modulated laser light is treated as an optical signal and, for example, modulated to indicate a control signal for an external device (described later) connected to the child node 13.

[0018] Child node 13 is installed at a predetermined location on network 11 away from parent node 12, and receives first laser light 15A and second laser light 15B. Child node 13 operates by optical power supply using first laser light 15A or second laser light 15B, and communicates with parent node 12 using first laser light 15A or second laser light 15B depending on the situation. Because the power required for operation of child node 13 is obtained from first laser light 15A or second laser light 15B, child node 13 does not require a power supply source other than power storage unit 47. In other words, the optical communication system according to this embodiment can eliminate the need for battery replacement and the installation of a power line to child node 13.

[0019] Child node 13 is configured to be capable of communication and power conversion using first laser light 15A and second laser light 15B, which have different wavelengths. Specifically, child node 13 employs a WDM coupler 42 to guide first laser light 15A and second laser light 15B, which have different wavelengths, to a single photoelectric conversion element 45. Therefore, even if child node 13 simultaneously receives first laser light 15A and second laser light 15B, attenuation of optical power due to optical interference between the two beams can be prevented because the two beams have different wavelengths. In other words, power conversion can be performed appropriately using each laser beam, preventing unexpected shutdown of child node 13 due to power shortages.

[0020] An external device (not shown) controlled by the child node 13 is connected to the child node 13. This external device is, for example, a route control device such as an optical switch or port monitoring device that connects or disconnects information communication networks, or a measuring device such as a thermometer or water level gauge used in a monitoring system. However, the external device controlled by the child node 13 is not limited to the above devices, and can be selected arbitrarily depending on the application of the optical communication system 10 as long as it is a device that can be driven by the child node 13.

[0021] The operation of the above external device is based on a control signal generated by the modulated first laser beam 15A or second laser beam 15B. The modulation of the laser beam to generate this control signal is performed by the parent node 12. In other words, the operation of the external device is controlled by remote operation from the parent node 12 via the child node 13. Therefore, an operator does not need to go to the installation location of the child node 13 to operate the external device. For example, if the external device is the above-mentioned route control device, route switching can be performed from a communication facility such as an exchange station.

[0022] Next, the operation of the optical communication system 10, that is, the optical power feeding method according to this embodiment, will be described. 2A and 2B are diagrams illustrating an example of the operation of the optical communication system 10. The optical communication system 10 according to this embodiment executes, as one step of an optical power supply method, switchable output of a first laser beam 15A to a first path 14A and output of a second laser beam 15B to a second path 14B. For example, the output of the first laser beam 15A and the output of the second laser beam 15B are alternately repeated. Meanwhile, as one step of the optical power supply method, each child node 13 converts the first laser beam 15A or the second laser beam 15B into electric power. The converted electric power is used as driving power for the child node 13. Therefore, even if a disconnection occurs in the network 11, optical communication between the parent node 12 and each child node 13 and optical power supply to each child node 13 can be continued by switching from one output of the first laser beam 15A to the other output of the second laser beam 15B.

[0023] For example, as shown in FIG. 2A, assume that a first laser beam 15A is output from parent node 12 to first path 14A. First laser beam 15A travels clockwise along first path 14A. In this situation, assume that a disconnection occurs in network 11 at point A between child node 13B and child node 13C. The parent node 12 can determine the occurrence of the disconnection, for example, when communication between parent node 12 and one of multiple child nodes 13 using first laser beam 15A or second laser beam 15B is interrupted. Note that the parent node 12 can also identify the location of the disconnection by attempting to communicate with multiple child nodes 13 in order along the path.

[0024] If a disconnection occurs at point A, parent node 12 will be unable to perform optical communication and optical power supply to two child nodes 13C and 13D, which are located downstream of point A in network 11. Therefore, as shown in FIG. 2B , parent node 12 switches the laser light path from first path 14A, which had been used until then, to second path 14B, and outputs second laser light 15B. Since second laser light 15B travels counterclockwise on second path 14B, optical communication between parent node 12 and child nodes 13C and 13D, and optical power supply to child nodes 13C and 13D, are restored. At this time, parent node 12 may notify an operator or the like of the occurrence of the disconnection.

[0025] Furthermore, the output of the first laser light 15A to the first path 14A and the output of the second laser light 15B to the second path 14B may be alternately repeated. This allows for continuous optical communication between the parent node 12 and all child nodes 13, and continuous optical power supply to all child nodes 13. In other words, it is possible to build an optical communication system 10 that can operate the child nodes 13 installed in the network 11 even if a disconnection occurs in the network 11.

[0026] Parent node 12 may alternately output first laser light 15A and second laser light 15B regardless of whether there is a break in network 11. In this case, first laser light 15A or second laser light 15B is continuously input to each child node. Therefore, optical communication between parent node 12 and all child nodes 13 and optical power supply to all child nodes 13 can be continued. Communication between parent node 12 and child node 13 using first laser light 15A or second laser light 15B also makes it possible to identify the occurrence of a break and its location.

[0027] Furthermore, parent node 12 may output both first laser light 15A and second laser light 15B when it determines that network 11 is disconnected. In this case, first laser light 15A or second laser light 15B is continuously input to each child node. Therefore, optical communication between parent node 12 and all child nodes 13 and optical power supply to all child nodes 13 can be continued.

[0028] Next, a specific configuration of the parent node 12 will be described. Fig. 3 is a diagram showing a first example of a specific configuration of parent node 12 and child node 13. As shown in Fig. 3, parent node 12 includes a first laser light source 21, a first modulator 22, a first optical circulator 23, a first photodetector 24, and a control unit 25. The control unit 25 is a so-called microcomputer, and performs overall control of each component such as first laser light source 21 provided in parent node 12 by reading and executing a program stored in advance in a memory or the like.

[0029] The first laser light source 21 generates a first laser light 15A and outputs the generated first laser light 15A to the first path 14A. The wavelength of the first laser light 15A may be a wavelength such as 1310 nm, 1490 nm, or 1550 nm, which is used in a PON system of an optical fiber network.

[0030] The first modulator 22 is a so-called electronic shutter, which performs on / off modulation on the first laser light 15A in response to a control signal from the control unit 25, and generates an optical signal directed to the child node 13. The first modulator 22 operates when communication is performed between the parent node 12 and the child node 13 using the first laser light 15A.

[0031] The first optical circulator 23 outputs the first laser light 15A output from the first laser light source 21 to the first path 14A. The first laser light 15A that has passed through the first optical circulator 23 is incident on an end of the first path 14A located at one end of the network 11. The first optical circulator 23 also outputs to the first photoreceiver 24 the reflected light of the first laser light 15A that has returned from the child node 13 via the first path 14A.

[0032] The first optical receiver 24 converts the reflected light of the first laser light 15A that arrives via the first optical circulator 23 into an electrical signal and outputs it to the control unit 25. The reflected light of the first laser light 15A is on / off modulated by the MEMS optical switch 46 provided in the child node 13.

[0033] The parent node 12 further comprises a second laser light source 26 , a second modulator 27 , a second optical circulator 28 , and a second optical receiver 29 .

[0034] Second laser light source 26 generates second laser light 15B and outputs the generated second laser light 15B to second path 14B. The wavelength of second laser light 15B may be the same as the wavelength of first laser light 15A, such as 1310 nm, 1490 nm, or 1550 nm. However, as described above, the wavelength of second laser light 15B is set to a value different from the wavelength of first laser light 15A.

[0035] Similarly to the first modulator 22, the second modulator 27 is also a so-called electronic shutter, which performs on / off modulation on the second laser light 15B in response to a control signal from the control unit 25, and generates an optical signal directed to the child node 13. The second modulator 27 operates when communication is performed between the parent node 12 and the child node 13 using the second laser light 15B.

[0036] Second optical circulator 28 outputs second laser light 15B output from second laser light source 26 to second path 14B. Second laser light 15B that passes through second optical circulator 28 is incident on an end of second path 14B located at the other end of network 11. Second optical circulator 28 also outputs reflected light of second laser light 15B that has returned from child node 13 via second path 14B to second photodetector 29.

[0037] The first laser light 15A is incident on an end of the first path 14A located at one end of the network 11, while the second laser light 15B is incident on an end of the second path 14B located at the other end of the network 11. Therefore, the first laser light 15A and the second laser light 15B traveling from the parent node 12 to each child node 13 travel in opposite directions on the network 11.

[0038] The second photodetector 29 converts the reflected light of the second laser light 15B that arrives via the second optical circulator 28 into an electrical signal and outputs it to the control unit 25. The reflected light of the second laser light 15B is on / off modulated by the MEMS optical switch 46 provided in the child node 13.

[0039] Next, a specific configuration of the child node 13 will be described. Each child node 13 includes an optical coupler 40, an optical coupler 41, a WDM coupler 42, an optical circulator 43, an optical coupler 44, an opto-electrical conversion element (first opto-electrical conversion element) 45, a MEMS optical switch 46, a power storage unit 47, and a control unit 48.

[0040] The optical coupler 40 splits the first laser light 15A that has passed through the first path 14A into two laser lights, and outputs one of the two laser lights to the WDM coupler 42. The optical coupler 40 also outputs the other of the two laser lights to the optical coupler 40 of the adjacent child node 13 (i.e., located downstream in the traveling direction of the first laser light 15A).

[0041] The optical coupler 41 splits the second laser light 15B that has passed through the second path 14B into two laser lights, and outputs one of the two laser lights to the WDM coupler 42. The optical coupler 41 also outputs the other of the two laser lights to the optical coupler 41 of the adjacent child node 13 (i.e., located downstream in the traveling direction of the second laser light 15B).

[0042] The WDM coupler 42 outputs the first laser light 15A and the second laser light 15B having different wavelengths to the optical circulator 43. That is, the WDM coupler 42 outputs the first laser light 15A output from the optical coupler 40 to the optical circulator 43. The WDM coupler 42 also outputs the second laser light 15B output from the optical coupler 41 to the optical circulator 43.

[0043] The optical circulator 43 outputs the first laser light 15A or the second laser light 15B output from the WDM coupler 42 to the optical coupler 44. The optical circulator 43 also outputs the first laser light 15A or the second laser light 15B output from the optical coupler 44 and reflected by the MEMS optical switch 46 to the WDM coupler 42.

[0044] Optical coupler 44 splits first laser light 15A or second laser light 15B output from optical circulator 43 into two laser lights, and outputs one of the two laser lights to photoelectric conversion element 45. Optical coupler 44 also outputs the other of the two laser lights to MEMS optical switch 46.

[0045] The photoelectric conversion element 45 converts the first laser beam 15A or the second laser beam 15B output from the optical coupler 44 into electrical energy. The converted electrical energy is output to the power storage unit 47. The photoelectric conversion element 45 outputs a portion of the converted electrical energy as an electrical signal to the control unit 48. When the first laser beam 15A is on / off modulated by the first modulator 22 of the parent node 12, the photoelectric conversion element 45 outputs an electrical signal that is on / off modulated in the same sequence. The control unit 48 receives this electrical signal and acquires various pieces of information from the parent node 12. The same applies when the second laser beam 15B is on / off modulated by the second modulator 27 of the parent node 12, and various pieces of information from the parent node 12 can be acquired.

[0046] The power storage unit 47 is, for example, a well-known capacitor, and stores the electrical energy output from the photoelectric conversion element 45. The power storage unit 47 functions as a power supply source for the child node 13. The power of the power storage unit 47 is supplied to the control unit 48, which operates in response to this power supply.

[0047] The control unit 48 is a so-called microcomputer that reads and executes a program stored in advance in a memory or the like to control the MEMS optical switch 46 and communicates with the parent node 12 using the first laser light 15A or the second laser light 15B. The control unit 48 also controls an external device connected to the child node 13 based on a control signal from the parent node 12 obtained through this communication. As described above, this external device is a route control device, a measurement device, or the like. The power storage unit 47 may supply power to the external device. In this case, there is no need to install power lines not only for the child node 13 but also for the external device.

[0048] The MEMS optical switch 46 has a large number of micromirrors formed by micromachining on a semiconductor. The angles of the micromirrors can be adjusted by a control unit 48. The MEMS optical switch 46 outputs the first laser light 15A or the second laser light 15B output from the optical coupler 44 to the optical circulator 43 while on-off modulating the first laser light 15A or the second laser light 15B under the control of the control unit 48.

[0049] The first laser light 15A or the second laser light 15B reflected by the MEMS optical switch 46 passes through the optical circulator 43 and enters the WDM coupler 42 again. The laser light that enters the WDM coupler 42 is output to the optical coupler 40 or the optical coupler 41 depending on its wavelength.

[0050] Specifically, when the first laser light 15A that has passed through the optical circulator 43 enters the WDM coupler 42, the first laser light 15A is output to the optical coupler 40. Thereafter, the first laser light 15A passes through the first path 14A (and the optical coupler 40 of another child node 13), and further passes through the first optical circulator 23 of the parent node 12, to be received by the first optical receiver 24 of the parent node 12. When the first laser light 15A received by the first optical receiver 24 is on-off modulated by the MEMS optical switch 46, the parent node 12 acquires various information indicated by this modulation.

[0051] On the other hand, when the second laser light 15B that has passed through the optical circulator 43 enters the WDM coupler 42, the second laser light 15B is output to the optical coupler 41. Thereafter, the second laser light 15B passes through the second path 14B (and the optical coupler 41 of another child node 13), and further passes through the second optical circulator 28 of the parent node 12, to be received by the second optical receiver 29 of the parent node 12. When the second laser light 15B received by the second optical receiver 29 is on / off modulated by the MEMS optical switch 46, the parent node 12 acquires various information indicated by this modulation.

[0052] 4 is a diagram showing a second example of the specific configuration of parent node 12 and child node 13. As shown in FIG. 4, parent node 12 according to the second example further includes an optical tester 30 and an optical channel selector 31 in addition to the configuration according to the first example. Note that optical tester 30 may be provided as a separate device connected to parent node 12.

[0053] The optical tester 30 is an optical time domain reflectometer (OTDR). The optical tester 30 irradiates a pulsed test light beam into the optical fiber under test, and identifies the presence or absence of a break in the optical fiber and the location of the break based on the intensity and round-trip time of backscattered light and Fresnel reflected light resulting from Rayleigh scattering of the test light.

[0054] The optical tester 30 of this example periodically inputs test light 52 to a third path 14C provided in the network 11 via an optical channel selector 31 and detects a break in the third path 14C. The third path 14C is laid along the first path 14A and the second path 14B and, like the first path 14A and the second path, passes through all child nodes 13. The optical channel selector 31 periodically switches the optical path of the test light 52, alternately inputting the test light 52 to one end and the other end of the third path 14C. This reduces the maximum distance from the optical tester 30 to the location of a break by half compared to when the optical path of the test light 52 is not alternately switched. This improves the sensitivity of break detection.

[0055] The third path 14C is located close to the first path 14A and the second path 14B between the child nodes 13. For example, the third path 14C, along with the first path 14A and the second path 14B, are housed in a single optical fiber cable. Therefore, if the third path 14C is disconnected, it is highly likely that the first path 14A and the second path 14B are also disconnected. Therefore, when the optical tester 30 detects a disconnection in the third path 14C, the control unit 25 of the parent node 12 determines that the first path 14A and the second path 14B are also disconnected. Based on this determination, the parent node 12 switches the laser light to be output from one of the first laser light 15A and the second laser light 15B to the other. For example, the parent node 12 may start alternately outputting the first laser light 15A and the second laser light 15B.

[0056] The optical tester 30 has a much higher detection sensitivity for disconnections than the communication using the first laser light 15A and the communication using the second laser light. In other words, it can detect disconnections in each direction with high sensitivity, and can more reliably supply optical power to all child nodes 13. When the optical tester 30 identifies the location of the disconnection, the parent node 12 may notify an operator or the like of the result.

[0057] 4, the parent node 12 according to the second example may further include a third laser light source 32 and an optical coupler 33. In this case, the child node 13 includes an optical coupler 49, a second opto-electrical conversion element 50, and a third opto-electrical conversion element 51 in addition to the above-described configuration according to the first example.

[0058] The third laser light source 32 generates a third laser light 15C used for optical power supply to the child node 13, and outputs the third laser light 15C to the third path 14C via the optical coupler 33 and the optical channel selector 31. The third laser light 15C may also have a wavelength such as 1310 nm, 1490 nm, or 1550 nm, similar to the wavelength of the first laser light 15A.

[0059] As described above, the optical channel selector 31 periodically switches the optical path. Therefore, the traveling direction of the third laser beam 15C on the third path 14C also periodically reverses. For ease of explanation, one of the two traveling directions of the third laser beam 15C is referred to as the first traveling direction, and the other is referred to as the second traveling direction. The first traveling direction and the second traveling direction are opposite to each other.

[0060] Optical coupler 49 is a so-called 2x2 optical coupler and is arranged on third path 14C. Optical coupler 49 splits third laser light 15C traveling in the first traveling direction into two laser lights and outputs one of the two laser lights to second optoelectric conversion element 50. Optical coupler 49 also outputs the other of the two laser lights to optical coupler 49 of the adjacent child node 13 (i.e., located downstream in the first traveling direction of third laser light 15C).

[0061] When the traveling direction of the third laser light 15C is reversed to the second traveling direction by the optical channel selector 31, the optical coupler 49 splits the third laser light 15C traveling in the second traveling direction into two laser lights, and outputs one of the two laser lights to the third opto-electric conversion element 51. The optical coupler 49 also outputs the other of the two laser lights to the optical coupler 49 of the adjacent child node 13 (i.e., located downstream in the second traveling direction of the third laser light 15C).

[0062] The second photoelectric conversion element 50 converts the third laser beam 15C output from the optical coupler 49 into electrical energy and outputs it to the power storage unit 47. Similarly, the third photoelectric conversion element 51 converts the third laser beam 15C output from the optical coupler 49 into electrical energy and outputs it to the power storage unit 47. Regardless of the direction of travel of the third laser beam 15C, either the second photoelectric conversion element 50 or the third photoelectric conversion element 51 performs photoelectric conversion, enabling continuous power storage. In other words, the third path can be used not only for disconnection inspection but also for optical power supply to the child node 13. Therefore, external devices that consume relatively high amounts of power can be powered solely by the power supplied from the child node 13.

[0063] The optical coupler 49 may be a so-called 2x2 optical switch. In this case, the control unit 25 of the child node 13 periodically switches the optical path in the 2x2 optical switch.

[0064] According to this embodiment, a ring-shaped network 11 is constructed in which a parent node 12 is the origin and multiple child nodes 13 are arranged side by side. Disconnections in the two paths that make up the network 11, i.e., the two optical fibers, can be detected directly or indirectly, and the optical power supply and optical communication paths can be switched to maintain optical power supply and optical communication to the child node 13. In addition, a WDM coupler 42 is employed as a component of the child node 13. As a result, two-way optical communication and optical power supply using light of different wavelengths are possible, and a redundant system that can avoid communication interference can be realized by driving using optical power supply. [Explanation of symbols]

[0065] 10 Optical Communication Systems 11 Network 12 Parent node (in-house node) 13 Child nodes (external nodes) 13A~13D Child nodes 14A 1st Route 14B 2nd route 14C 3rd route 15A First laser beam 15B Second laser beam 15C Third laser beam 21 First laser light source 22 First Modulator 23 First Optical Circulator 24 1st receiver 25 Control Unit 26 Second laser light source 27 Second Modulator 28 Second Optical Circulator 29 2nd receiver 30 Optical Tester 31 Optical Channel Selector 32 Third laser light source 33 Optical Coupler 40 Optical Coupler 41 Optical Coupler 42 WDM coupler 43 Optical Circulator 44 Optical Coupler 45 Photoelectric conversion element (first photoelectric conversion element) 46 MEMS optical switch 47 Power storage unit 48 Control Unit 49 Optical Coupler 50 Second photoelectric conversion element 51 Third photoelectric conversion element 52 Test Light

Claims

1. An optical communication system in a ring network, a parent node that switchably outputs a first laser beam to a first route in the network and a second laser beam to a second route in the network; a plurality of child nodes that operate by optical power supply from the first laser light or the second laser light; Equipped with the first laser light and the second laser light have different wavelengths, The first laser light and the second laser light traveling from the parent node to each of the child nodes are different in traveling direction from each other. Optical communication system.

2. 2. The optical communication system according to claim 1, an optical tester that detects a disconnection in the network by using test light output to a third path in the network; When the optical tester detects a disconnection in the network, the parent node switches the output of the first laser light and the second laser light from one to the other. Optical communication system.

3. 2. The optical communication system according to claim 1, an optical tester that detects a disconnection in the network by using test light output to a third path in the network; When the optical tester detects a break in the network, the parent node outputs the first laser light and the second laser light. Optical communication system.

4. 3. The optical communication system according to claim 2, the parent node outputs a third laser beam to the third route; Each of the child nodes stores the power obtained by optical power supply from the third laser light. Optical communication system.

5. 4. The optical communication system according to claim 3, the parent node outputs a third laser beam to the third route; Each of the child nodes stores the power obtained by optical power supply from the third laser light. Optical communication system.

6. An optical communication system according to any one of claims 1 to 5, Each of the child nodes controls an external device connected to the child node based on a control signal obtained through communication with the parent node. Optical communication system.

7. An optical power supply method in a ring network, comprising: outputting a first laser beam from a parent node to a plurality of child nodes via a first path of the network and outputting a second laser beam from the parent node to each of the child nodes via a second path of the network in a switchable manner; converting the first laser light or the second laser light into electric power at each of the child nodes; the first laser light and the second laser light have different wavelengths, The first laser light and the second laser light traveling from the parent node to each of the child nodes are different in traveling direction from each other. Optical power supply method.

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