Optical communication device and optical communication system

Abstract

An optical communication device (16) according to an embodiment is provided with: a communication circuit (22) for transmitting and receiving a signal using a first communication optical fiber (14A) connected to a first port (18); a tester circuit (24) for transmitting and receiving a test signal using a loop-back optical fiber (30) connected to a second port (20); a determining unit (26) which, when the amount of optical reception of the test signal is lower than a threshold value, determines that the loop-back optical fiber (30) is degraded; and a notifying unit (28) for notifying a determination result from the determining unit (26).

Description

[Technical field]

[0001] The present invention relates to an optical communication device and an optical communication system that communicates via a communication optical fiber. [Background technology]

[0002] Japanese Utility Model Application Publication No. 64-046915 discloses an optical fiber composite overhead conductor. The optical fiber composite overhead conductor contains a communication optical fiber for signal transmission and a monitor optical fiber for life estimation. The optical fiber has a service life that can withstand a required life. According to Japanese Utility Model Application Publication No. 64-046915, the service life of the optical fiber cable is estimated using a monitor optical fiber with a service life shorter than that of the communication optical fiber. Summary of the Invention

[0003] However, the optical fiber composite overhead conductor disclosed in Japanese Utility Model Application Laid-Open Publication No. 64-046915 has a built-in optical fiber for communication and an optical fiber for monitoring, so the diameter of the optical fiber composite overhead conductor tends to be large. Also, it is difficult to build an optical fiber for monitoring into an existing optical fiber for communication.

[0004] SUMMARY OF THE PRESENT EMBODIMENTS The present invention has an object to provide an optical communication device and an optical communication system that are capable of detecting an abnormality in an existing communication optical fiber at an early stage even if the existing communication optical fiber is used as is.

[0005] A first aspect of the present invention is an optical communication device, comprising: a first port having a first light emitting element and a first light receiving element and to which a first communication optical fiber is connected; a loopback optical fiber having a larger optical attenuation per unit distance than the first communication optical fiber; a second port having a second light emitting element and a second light receiving element and to which the loopback optical fiber is connected; a communication circuit that transmits a transmission signal to the first communication optical fiber using the first light-emitting element and receives a reception signal from the first communication optical fiber using the first light-receiving element; a tester circuit that transmits a test signal to the loopback optical fiber using the second light-emitting element and receives the test signal from the loopback optical fiber using the second light-receiving element; a determination unit that determines that the loopback optical fiber is deteriorated when the amount of light received by the second light receiving element falls below a threshold value; A notification unit that notifies a judgment result of the judgment unit; Equipped with.

[0006] A second aspect of the present invention is an optical communication system including a plurality of optical communication units that are daisy-chained together via communication optical fibers and capable of transmitting and receiving signals to and from each other, At least one of the plurality of optical communication units is provided with the optical communication device described above.

[0007] According to the aspects of the present invention, when it is determined that the loopback optical fiber is deteriorated, the operator is alerted to the possibility of deterioration of the communication optical fiber, and an opportunity for inspection, etc. As a result, even if the existing communication optical fiber is used as is, an abnormality in the communication optical fiber can be found at an early stage. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a block diagram showing an optical communication system according to an embodiment. [Diagram 2] FIG. 2 is a block diagram showing an optical communication device. [Diagram 3] FIG. 3 is a block diagram showing an optical communication device provided in an optical communication unit between a front optical communication unit and a last optical communication unit. [Figure 4] FIG. 4 is a block diagram showing a modified example of the optical communication device provided in the last optical communication unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] [Embodiment] 1 is a block diagram showing an optical communication system 10 according to an embodiment. The optical communication system 10 includes a plurality of optical communication units 12. The plurality of optical communication units 12 are connected in a daisy chain via a communication optical fiber 14. In other words, the plurality of optical communication units 12 are connected in series in a daisy chain via the communication optical fiber 14. The communication optical fiber 14 may be composed of one optical fiber for transmission and reception, or may be composed of two optical fibers, an optical fiber for transmission and an optical fiber for reception.

[0010] The optical communication units 12 can transmit and receive signals to and from each other. For example, the foremost (first) optical communication unit 12 of the optical communication units 12 connected in a daisy chain can transmit and receive signals to and from the second optical communication unit 12. Furthermore, the last optical communication unit 12 of the optical communication units 12 connected in a daisy chain can transmit and receive signals to and from the optical communication unit 12 disposed one step ahead of the last optical communication unit 12. Furthermore, the optical communication units 12 other than the foremost optical communication unit 12 and the last optical communication unit 12 of the optical communication units 12 connected in a daisy chain can transmit and receive signals to and from both the optical communication unit 12 immediately preceding it and the optical communication unit 12 immediately following it.

[0011] In this embodiment, the number of optical communication units 12 is four. In this embodiment, the first optical communication unit 12 is a master unit, and the second to fourth optical communication units 12 are slave units. The master unit controls communication of each of the optical communication units 12. The slave units operate under the control of the master unit.

[0012] For example, when the forefront optical communication unit 12 communicates with the fourth optical communication unit 12, the forefront optical communication unit 12 controls the second optical communication unit 12 and the third optical communication unit 12. In this case, the forefront optical communication unit 12 causes the second optical communication unit 12 and the third optical communication unit 12 to relay information to be transmitted and received between the forefront optical communication unit 12 and the fourth optical communication unit 12. Also, for example, when the forefront optical communication unit 12 communicates with the second optical communication unit 12, the forefront optical communication unit 12 does not control the third optical communication unit 12 and the fourth optical communication unit 12. In this case, the third optical communication unit 12 and the fourth optical communication unit 12 do not operate. The forefront optical communication unit 12 transmits and receives information to and from the second optical communication unit 12.

[0013] Fig. 2 is a block diagram showing the optical communication device 16. In this embodiment, the optical communication device 16 is provided in the last optical communication unit 12 (the fourth optical communication unit 12) (see Fig. 1).

[0014] The optical communication device 16 has a first port 18, a second port 20, a communication circuit 22, a tester circuit 24, a determination unit 26, and a notification unit .

[0015] The first port 18 is a port to which a first communication optical fiber 14A for communicating with the optical communication unit 12 can be connected. The first port 18 has a first light-emitting element 18A and a first light-receiving element 18B. In this embodiment, the optical communication device 16 is capable of communicating with a third optical communication unit 12 (see FIG. 1) via the first communication optical fiber 14A connected to the first port 18.

[0016] The second port 20 is a port to which a loopback optical fiber 30, which has a larger amount of optical attenuation per unit distance than the first communication optical fiber 14A, can be connected. The second port 20 has a second light-emitting element 20A and a second light-receiving element 20B. In this embodiment, since the last optical communication unit 12 is provided with an optical communication device 16, the second port 20 is an empty port to which the communication optical fiber 14 is not connected. The loopback optical fiber 30 is connected to this empty port.

[0017] As a method for making the optical attenuation per unit distance of the loopback optical fiber 30 larger than the optical attenuation per unit distance of the first communication optical fiber 14A, any one of the following methods can be adopted. It should be noted that a combination of two or more methods may be adopted. The first method is to make the bending radius of the loopback optical fiber 30 smaller than that of the first communication optical fiber 14A. The second method is to make the fiber diameter of the loopback optical fiber 30 smaller. The third method is to use a material for the loopback optical fiber 30 that has a larger attenuation than that of the material used for the first communication optical fiber 14A. The fourth method is to increase the spatial transmission length from the fiber end of the loopback optical fiber 30 to at least one of the second light-emitting element 20A and the second light-receiving element 20B. The fifth method is to cut the fiber end of the loopback optical fiber 30 obliquely. As a sixth method, the fiber end of the loopback optical fiber 30 is subjected to a scratching process such as a grinding process.

[0018] The communication circuit 22 is a circuit that transmits a transmission signal to the first communication optical fiber 14A using the first light-emitting element 18A and receives a reception signal from the first communication optical fiber 14A using the first light-receiving element 18B. The communication circuit 22 outputs an optical signal corresponding to the transmission signal to the first communication optical fiber 14A by controlling the first light-emitting element 18A based on the transmission signal. The communication circuit 22 obtains a reception signal corresponding to the transmission signal based on the optical signal emitted from the first communication optical fiber 14A and received by the first light-receiving element 18B.

[0019] The tester circuit 24 is a circuit that transmits a test signal to the loopback optical fiber 30 using the second light-emitting element 20A and receives the test signal from the loopback optical fiber 30 using the second light-receiving element 20B. The tester circuit 24 controls the second light-emitting element 20A based on the test signal, thereby outputting an optical signal corresponding to the test signal to the loopback optical fiber 30. The tester circuit 24 acquires the test signal based on the optical signal emitted from the loopback optical fiber 30 and received by the second light-receiving element 20B.

[0020] The timing at which the tester circuit 24 transmits the test signal may be when it receives a command to transmit a test signal output from the operation unit in response to an operator's operation, or when a predetermined period has elapsed.

[0021] The determination unit 26 determines that the loopback optical fiber 30 is degraded when the amount of light received by the second light receiving element 20B falls below a threshold. Some light receiving elements perform photoelectric conversion and output a signal when the intensity is equal to or greater than a predetermined intensity, and do not output a signal when the intensity is less than the predetermined intensity because they cannot perform photoelectric conversion. When such a light receiving element is used as the second light receiving element 20B, the amount of light received by the second light receiving element 20B falls below the threshold when no signal is output from the second light receiving element 20B.

[0022] The notification unit 28 notifies the judgment result of the judgment unit 26. The notification unit 28 notifies that the loopback optical fiber 30 is deteriorated by using at least one of the speaker, the light-emitting unit, and the display unit. At least one of the speaker, the light-emitting unit, and the display unit may be provided in the optical communication device 16, or may be provided in the last optical communication unit 12 (see FIG. 1). At least one of the speaker, the light-emitting unit, and the display unit may be provided in an optical communication unit 12 other than the last optical communication unit 12. When at least one of the speaker, the light-emitting unit, and the display unit is provided in an optical communication unit 12 other than the last optical communication unit 12, the notification unit 28 controls the communication circuit 22. In this case, the notification unit 28 notifies the judgment result of the judgment unit 26 by transmitting an activation signal to the optical communication unit 12 other than the last optical communication unit 12 via the first communication optical fiber 14A.

[0023] The notification unit 28 may control the speaker to output a sound to the effect that the loopback optical fiber 30 is degraded. The notification unit 28 may also control the light-emitting unit to have a color, brightness, number of flashes per unit time, or the like that indicate that the loopback optical fiber 30 is degraded. The notification unit 28 may also control the display unit to display a message to the effect that the loopback optical fiber 30 is degraded on a display screen.

[0024] As described above, the optical communication device 16 of this embodiment transmits a test signal to the loopback optical fiber 30, which has a larger amount of optical attenuation per unit distance than the first communication optical fiber 14A. When the amount of light corresponding to the test signal received by the second light receiving element 20B falls below a threshold, the optical communication device 16 determines that the loopback optical fiber 30 is deteriorated and notifies the determination result.

[0025] As a result, when it is determined that the loopback optical fiber 30 is deteriorated, the operator is alerted to the possibility of deterioration in the first communication optical fiber 14A, and an opportunity for inspection, etc. As a result, according to this embodiment, even if the existing communication optical fiber 14 is used as is, an abnormality in the communication optical fiber 14 can be found early.

[0026] [Modifications] The above embodiment may be modified as follows.

[0027] (Variation 1) 3 is a block diagram showing an optical communication device 16 provided in an optical communication unit 12 between a first optical communication unit 12 and a last optical communication unit 12. In this modification, the optical communication unit 12 between the first optical communication unit 12 and the last optical communication unit 12 is referred to as an intermediate communication unit 12. In the case of the optical communication system 10 shown in FIG. 1, the intermediate communication unit 12 is the second optical communication unit 12 or the third optical communication unit 12. In FIG. 3, the same reference numerals are used for configurations equivalent to those described above. Note that in this modification, explanations that overlap with those described above will be omitted.

[0028] The optical communication device 16 provided in the intermediate communication unit 12 further includes a third port 32. The third port 32 is a port to which a third communication optical fiber 14C for communicating with the optical communication unit 12 can be connected. The third port 32 has a third light-emitting element 32A and a third light-receiving element 32B. The third port 32 is connected to the third communication optical fiber 14C. The optical communication device 16 can communicate with the optical communication unit 12 arranged one step behind the intermediate communication unit 12 via the third communication optical fiber 14C connected to the third port 32. The optical communication device 16 can communicate with the optical communication unit 12 arranged one step ahead of the intermediate communication unit 12 via the first communication optical fiber 14A connected to the first port 18.

[0029] That is, the communication circuit 22 can transmit a transmission signal to the third communication optical fiber 14C using the third light-emitting element 32A, and can receive a reception signal from the third communication optical fiber 14C using the third light-receiving element 32B. On the other hand, the communication circuit 22 can transmit a transmission signal to the first communication optical fiber 14A using the first light-emitting element 18A, and can receive a reception signal from the first communication optical fiber 14A using the first light-receiving element 18B.

[0030] As in the above embodiment, the optical communication device 16 provided in the intermediate communication unit 12 is provided with the tester circuit 24, the determination unit 26, and the notification unit 28. Therefore, even if the intermediate communication unit 12 is provided with the optical communication device 16, as in the above embodiment, an abnormality in the communication optical fiber 14 can be found early even if the existing communication optical fiber 14 is used as is.

[0031] (Variation 2) Fig. 4 is a block diagram showing a modified example of the optical communication device 16 provided in the last optical communication unit 12. In Fig. 4, the same components as those described above are denoted by the same reference numerals. Note that in this modified example, explanations that overlap with those described above will be omitted.

[0032] The second port 20 can be connected to the second communication optical fiber 14B instead of the loopback optical fiber 30. In this case, one or more optical communication units 12 can be newly connected in a daisy chain after the last optical communication unit 12 in the above embodiment. In other words, the last optical communication unit 12 in the above embodiment can be configured as the intermediate communication unit 12.

[0033] Therefore, in this modified example, a switching unit 34 is newly provided. The switching unit 34 switches the connection with the second port 20 between the tester circuit 24 and the communication circuit 22. In other words, the switching unit 34 switches whether the transmission and reception of signals using the second light-emitting element 20A and the second light-receiving element 20B is performed using the tester circuit 24 or the communication circuit 22.

[0034] The switching unit 34 detects the optical fiber connected to the second port 20. When the optical fiber connected to the second port 20 is the loopback optical fiber 30, the switching unit 34 connects the tester circuit 24 to the second port 20. On the other hand, when the optical fiber connected to the second port 20 is the second communication optical fiber 14B, the switching unit 34 connects the communication circuit 22 to the second port 20. When the optical fiber connected to the second port 20 cannot be detected, the switching unit 34 may connect the tester circuit 24 or the communication circuit 22 to the second port 20 in response to an operation by an operator.

[0035] When the communication circuit 22 is connected to the second port 20, the communication circuit 22 transmits a transmission signal to the second communication optical fiber 14B using the second light-emitting element 20A. Also, the communication circuit 22 receives a reception signal from the second communication optical fiber 14B using the second light-receiving element 20B.

[0036] Thus, according to this modification, the same effects as those of the above embodiment can be obtained regardless of which of the multiple optical communication units 12 connected in a daisy chain is provided with the optical communication device 16.

[0037] (Variation 3) The optical communication device 16 of the above embodiment may be provided in the forefront optical communication unit 12. Even if the optical communication device 16 of the above embodiment is provided in the forefront optical communication unit 12, the same results as the embodiment can be obtained. Furthermore, the optical communication device 16 of the modified example 2 may be provided in the forefront optical communication unit 12. When the optical communication device 16 of the modified example 2 is provided in the forefront optical communication unit 12, the first port 18 does not need to be provided. In this case, the optical communication device 16 of the above embodiment is provided in at least one of the optical communication units 12 other than the forefront optical communication unit 12.

[0038] (Variation 4) In the above embodiment or modification 1, the second port 20 may be a dedicated port for the loopback optical fiber 30. In this case, the second light-emitting element 20A may emit light with a lower emission intensity than the first light-emitting element 18A of the first port 18. This makes it possible to adjust the degree to which it is determined that the loopback optical fiber 30 is deteriorated depending on the type of the second light-emitting element 20A, etc.

[0039] Furthermore, when the second port 20 is a dedicated port for the loopback optical fiber 30, the second light receiving element 20B may have a lower light receiving sensitivity than the first light receiving element 18B of the first port 18. This makes it possible to adjust the degree to which it is determined that the loopback optical fiber 30 is deteriorated, depending on the type of the second light receiving element 20B, etc.

[0040] (Variation 5) The determination unit 26 may change the threshold value for determining that the loopback optical fiber 30 is degraded in response to an operation by an operator. This makes it possible to adjust the degree to which the loopback optical fiber 30 is determined to be degraded in response to the environment in which the optical communication system 10 is placed, etc.

[0041] (Variation 6) The above embodiment and modifications 1 to 5 may be combined in any manner as long as no contradiction occurs.

[0042] As inventions that can be understood from the embodiments and modifications, a first invention and a second invention will be described below.

[0043] (First invention) The first invention is an optical communication device (16), comprising: a first port (18) having a first light-emitting element (18A) and a first light-receiving element (18B) and to which a first communication optical fiber (14A) is connected; a loopback optical fiber (30) having a larger amount of light attenuation per unit distance than the first communication optical fiber; a second port (20) having a second light-emitting element (20A) and a second light-receiving element (20B) and to which the loopback optical fiber is connected; and a first light-emitting element (18A) and a first light-receiving element (18B) for transmitting a transmission signal to the first communication optical fiber (14A) using the first light-emitting element. and receives a received signal from the first communication optical fiber using a first light receiving element; a tester circuit (24) that transmits a test signal to the loopback optical fiber using a second light emitting element and receives the test signal from the loopback optical fiber using the second light receiving element; a judgment unit (26) that judges that the loopback optical fiber has deteriorated when the amount of light received by the second light receiving element falls below a threshold; and a notification unit (28) that notifies the judgment result of the judgment unit.

[0044] As a result, when it is determined that the loopback optical fiber is deteriorated, the operator is alerted to the possibility of deterioration in the communication optical fiber, and an opportunity for inspection, etc. As a result, even if the existing communication optical fiber is used as is, abnormalities in the communication optical fiber can be discovered early.

[0045] A second communication optical fiber (14B) can be connected to the second port instead of the loopback optical fiber, the communication circuit can transmit a transmission signal to the second communication optical fiber using the second light-emitting element and receive a reception signal from the second communication optical fiber using the second light-receiving element, and the optical communication device may include a switching unit (34) that switches the connection with the second port to the tester circuit or the communication circuit. This makes it possible to detect abnormalities in the communication optical fiber at an early stage, even if an optical communication device is provided in any of a plurality of optical communication units connected in a daisy chain, and even if the existing communication optical fiber is used as is.

[0046] The optical communication device may have a third light emitting element (32A) and a third light receiving element (32B) and include a third port (32) to which a third communication optical fiber (14C) is connected, and the communication circuit may transmit a transmission signal to the third communication optical fiber using the third light emitting element and receive a reception signal from the third communication optical fiber using the third light receiving element. In this way, the first optical communication unit among the multiple optical communication units connected in a daisy chain may be connected to the third port (32). unit And the last optical communication unit Even if an optical communication device is provided in the optical communication unit between the communication optical fiber and the optical communication device, an abnormality in the communication optical fiber can be detected early even if the existing communication optical fiber is used as it is.

[0047] The second light emitting element may emit light having a lower emission intensity than the first light emitting element, thereby making it possible to adjust the degree to which it is determined that the loopback optical fiber is deteriorated depending on the type of the second light emitting element, etc.

[0048] The second light receiving element may have a lower light receiving sensitivity than the first light receiving element, which makes it possible to adjust the degree to which it is determined that the loopback optical fiber has deteriorated depending on the type of the second light receiving element, etc.

[0049] (Second Invention) The second invention is an optical communication system (10) including a plurality of optical communication units (12) that are daisy-chained together via communication optical fibers (14) and can transmit and receive signals to and from each other. At least one of the plurality of optical communication units is provided with the optical communication device described above. Since the optical communication device described above is provided, abnormalities in the communication optical fibers can be detected early even if existing communication optical fibers are used as they are.

[0050] The first optical communication unit among the multiple optical communication units connected in a daisy chain is a master unit that controls communication of each of the multiple optical communication units, and at least the last optical communication unit among the multiple optical communication units connected in a daisy chain is equipped with an optical communication device equipped with the above-mentioned switching unit. As a result, regardless of which of the multiple optical communication units connected in a daisy chain is equipped with an optical communication device, it is possible to detect abnormalities in the communication optical fiber at an early stage using the existing communication optical fiber as it is.

Claims

1. a first port (18) having a first light emitting element (18A) and a first light receiving element (18B) and to which a first communication optical fiber (14A) is connected; a loopback optical fiber (30) having a larger amount of optical attenuation per unit distance than the first communication optical fiber; a second port (20) having a second light emitting element (20A) and a second light receiving element (20B) and to which the loopback optical fiber is connected; a communication circuit (22) that transmits a transmission signal to the first communication optical fiber using the first light-emitting element and receives a reception signal from the first communication optical fiber using the first light-receiving element; a tester circuit (24) that transmits a test signal to the loopback optical fiber using the second light-emitting element and receives the test signal from the loopback optical fiber using the second light-receiving element; a determination unit (26) that determines that the loopback optical fiber is deteriorated when the amount of light received by the second light receiving element falls below a threshold value; A notification unit (28) that notifies the determination result of the determination unit; An optical communication device (16).

2. 2. The optical communication device according to claim 1, A second communication optical fiber (14B) can be connected to the second port instead of the loopback optical fiber; the communication circuit is capable of transmitting a transmission signal to the second optical fiber for communication using the second light-emitting element and receiving a reception signal from the second optical fiber for communication using the second light-receiving element; a switching unit (34) for switching a connection with the second port to the tester circuit or the communication circuit; An optical communication device comprising:

3. 2. The optical communication device according to claim 1, a third port (32) having a third light emitting element (32A) and a third light receiving element (32B) and to which a third communication optical fiber (14C) is connected; The communication circuit transmits a transmission signal to the third optical fiber for communication using the third light-emitting element, and receives a reception signal from the third optical fiber for communication using the third light-receiving element.

4. 4. The optical communication device according to claim 1, The second light-emitting element emits light having a lower emission intensity than the first light-emitting element.

5. 5. An optical communication device according to claim 1, 3 or 4, An optical communication device, wherein the second light receiving element has a light receiving sensitivity lower than that of the first light receiving element.

6. An optical communication system (10) including a plurality of optical communication units (12) connected in a daisy chain via a communication optical fiber (14) and capable of transmitting and receiving signals to and from each other, An optical communication system, wherein at least one of the plurality of optical communication units is provided with the optical communication device according to any one of claims 1 to 5.

7. 7. The optical communication system according to claim 6, the first optical communication unit among the plurality of optical communication units connected in a daisy chain is a master unit that controls communication of each of the plurality of optical communication units; An optical communication system, wherein at least a last one of the plurality of optical communication units connected in a daisy chain is provided with the optical communication device according to claim 2 .

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