Optical communication system, optical communication method, and optical transmitter

Abstract

To realize an optical communication system that reduces the possibility of signal light entering the eyes of workers. [Solution] An optical communication system (1) according to one embodiment of the present invention includes an optical communication path (11), an electrical communication path (12), an optical receiver (14) optically connected to one end of the optical communication path (11) and electrically connected to one end of the electrical communication path (12), and an optical transmitter (13) optically connected to the other end of the optical communication path (11) and electrically connected to the other end of the electrical communication path (12), and the optical transmitter (13) performs a data signal transmission process of transmitting a data signal, which is an optical signal, to the optical receiver (14) via the optical communication path (11) only when the optical transmitter (13) is electrically connected to the optical receiver (14) via the electrical communication path (12).

Description

[Technical Field]

[0001] The present disclosure relates to an optical communication system realized by optically connecting an optical transmitter and an optical receiver via an optical communication path and electrically connecting them via an electrical communication path, and also to an optical communication method in such an optical communication system and an optical transmitter included in such an optical communication system. [Background technology]

[0002] Optical communication systems that transmit data signals using optical communication paths such as optical fibers are widely used. For example, Patent Document 1 discloses a data transmission device in which a camera-side connector and a processing device-side connector are optically connected using optical fibers and electrically connected using differential lines. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-60522 (Patent No. 4898948) DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0004] In an optical communication system in which an optical transmitter and an optical receiver are optically connected using an optical communication path and electrically connected using an electrical communication path, such as the data transmission device described in Patent Document 1, a data signal, which is an optical signal, is transmitted via the optical communication path, and a control signal, which is an electrical signal, is transmitted via the electrical communication path.

[0005] In such optical communication systems, optical connectors are provided at both ends or in the middle of the optical communication path, and electrical connectors are provided at both ends or in the middle of the electrical communication path. If an operator disconnects an optical connector during data signal transmission, the signal light may be incident on the operator's eyes. To prevent this from happening, the optical receiver is equipped with a function that transmits a Loss of Signal (LOS) signal to the optical transmitter via the electrical communication path when it detects a data signal interruption. The optical transmitter is also equipped with a function that halts or interrupts the transmission of the data signal via the optical communication path when it detects an LOS signal. This reduces the possibility of the signal light being incident on the operator's eyes.

[0006] However, if the electrical connector is also disconnected when the optical connector is disconnected, the optical transmitter cannot receive the LOS signal transmitted from the optical receiver, and as a result, the optical transmitter cannot stop or suspend the transmission of the data signal, which makes it impossible to reduce the possibility of the signal light hitting the worker's eyes.

[0007] The present disclosure has been made in consideration of the above-mentioned problems, and one of its objectives is to realize an optical communication system that reduces the possibility of signal light being incident on an operator's eyes. [Means for solving the problem]

[0008] An optical communication system according to one aspect of the present invention includes an optical communication path, an electrical communication path, an optical receiver optically connected to one end of the optical communication path and electrically connected to one end of the electrical communication path, and an optical transmitter optically connected to the other end of the optical communication path and electrically connected to the other end of the electrical communication path, wherein the optical transmitter performs a data signal transmission process of transmitting a data signal, which is an optical signal, to the optical receiver via the optical communication path only when the optical transmitter is electrically connected to the optical receiver via the electrical communication path. [Effects of the Invention]

[0009] According to one aspect of the present disclosure, an optical communication system can be realized that reduces the possibility of signal light entering the eyes of a worker. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a block diagram showing a configuration of an optical communication system according to an embodiment of the present invention. [Figure 2] FIG. 2 is a block diagram showing a specific example of the optical communication system shown in FIG. [Figure 3] 2 is a flowchart showing the flow of operations at the start of communication of an optical transmitter included in the optical communication system shown in FIG. [Figure 4] 4 is a flowchart showing a modified example of the operation of the optical transmitter shown in FIG. 3. [Figure 5] 1. FIG. 4 is a flowchart showing the flow of operations after communication is interrupted in an optical transmitter included in the optical communication system shown in FIG. [Figure 6] 6 is a flowchart showing a modified example of the operation of the optical transmitter shown in FIG. 5. [Figure 7] 2 is a cross-sectional view showing a cross section of a composite cable in which an optical transmitter and an optical receiver included in the optical communication system shown in FIG. 1 are housed. DETAILED DESCRIPTION OF THE INVENTION

[0011] (Configuration of optical communication system) The configuration of an optical communication system 1 according to one embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a block diagram showing the configuration of the optical communication system 1.

[0012] As shown in FIG. 1, the optical communication system 1 includes an optical communication path 11, an electrical communication path 12, an optical transmitter 13, and an optical receiver 14.

[0013] The optical communication path 11 is a communication path for transmitting an optical signal. As an example, the optical communication path 11 is an optical fiber. The optical communication path 11 may be housed in an optical cable, or may be housed in a composite cable together with the electrical communication path 12. The electrical communication path 12 is a communication path for transmitting an electrical signal. As an example, the electrical communication path 12 is a metal wire. The electrical communication path 12 may be housed in an electrical cable, or may be housed in a composite cable together with the optical communication path 11.

[0014] An optical transmitter 13 is optically connected to one end of the optical communication path 11. The optical connection between the optical communication path 11 and the optical transmitter 13 is realized, for example, by mating an optical connector 11a provided at one end of the optical communication path 11 with an optical connector 131 provided at the optical transmitter 13. Furthermore, an optical receiver 14 is optically connected to the other end of the optical communication path 11. The optical connection between the optical communication path 11 and the optical receiver 14 is realized, for example, by mating an optical connector 11b provided at the other end of the optical communication path 11 with an optical connector 141 provided at the optical receiver 14.

[0015] The optical communication path 11 may be divided into a first section Ia on the optical transmitter 13 side and a second section Ib on the optical receiver 14 side. In this case, the optical connection between the first section Ia and the second section Ib is realized by mating an optical connector 11c provided at one end of the first section Ia (the end opposite to the optical connector 11a side) with an optical connector 11d provided at one end of the second section Ib (the end opposite to the optical connector 11b side).

[0016] An optical transmitter 13 is electrically connected to one end of the electrical communication path 12. The electrical connection between the electrical communication path 12 and the optical transmitter 13 is realized, for example, by mating an electrical connector 12a provided at one end of the electrical communication path 12 with an electrical connector 132 provided on the optical transmitter 13. An optical receiver 14 is electrically connected to the other end of the electrical communication path 12. The electrical connection between the electrical communication path 12 and the optical receiver 14 is realized, for example, by mating an electrical connector 12b provided at the other end of the electrical communication path 12 with an electrical connector 142 provided on the optical receiver 14.

[0017] The electrical communication path 12 may be divided into a first section Ja on the optical transmitter 13 side and a second section Jb on the optical receiver 14 side. In this case, the electrical connection between the first section Ja and the second section Jb is realized by mating an electrical connector 12c provided at one end of the first section Ja (the end opposite the electrical connector 12a side) with an electrical connector 12d provided at one end of the second section Jb (the end opposite the electrical connector 12b side).

[0018] As shown in FIG. 1, the optical transmitter 13 includes an optical signal transmitting unit 133, an electrical signal receiving unit 134, and a control unit 135.

[0019] The optical signal transmitting unit 133 is configured to transmit an optical signal to the optical receiver 14 via the optical communication path 11. The optical signal transmitting unit 133 can be realized, for example, by a known optical modulation circuit. The optical signal transmitting unit 133 executes a data signal transmission process and a test signal transmission process. The data signal transmission process is a process of transmitting a data signal, which is an optical signal, to the optical receiver 14 via the optical communication path 11. The test signal transmission process is a process of transmitting a test signal, which is an optical signal with lower power than the data signal, to the optical receiver 14 via the optical communication path 11.

[0020] The test signal is, for example, a pulse signal. In this case, methods for making the power (energy per unit time) of the test signal smaller than the power of the data signal include, for example, (1) making the peak value of the test signal smaller than the peak value of the data signal, (2) making the pulse width of the test signal shorter than the pulse width of the data signal, and (3) making the pulse period of the test signal longer than the pulse period of the data signal. In this embodiment, a short pulse signal with a pulse width shorter than that of the data signal is used as the test signal.

[0021] It is preferable that the power of the test signal be ⅓ or less of the power of the data signal. A power supply circuit failure, a short circuit in a peripheral circuit, or the like may cause the magnitude of the drive current flowing into the light-emitting element included in the optical signal transmission unit 133 to increase to approximately three times the expected value. Even in such a case, if the power of the test signal is ⅓ or less of the power of the data signal, the power of the test signal can be kept below the power of the data signal. Depending on the circuit design, the magnitude of the drive current flowing into the light-emitting element included in the optical signal transmission unit 133 may increase to approximately n (n is an integer greater than or equal to 1) times the expected value. In such a case, if the power of the test signal is ⅓ or less of the power of the data signal, the power of the test signal can be kept below the power of the data signal.

[0022] The electrical signal receiving unit 134 is configured to receive an electrical signal from the optical receiver 14 via the electrical communication path 12. The electrical signal receiving unit 134 can be realized by, for example, a known electrical demodulation circuit. An example of the electrical signal received by the electrical signal receiving unit 134 is a control signal, which is an electrical signal transmitted by the optical receiver 14 in a control signal transmission process described below.

[0023] The control unit 135 is configured to permit or prohibit the execution of a data signal transmission process by the optical signal transmission unit 133. The control unit 135 can be realized by, for example, a known microcomputer.

[0024] In this embodiment, the control unit 135 supplies a TxDisable signal to the optical signal transmission unit 133. The TxDisable signal is a binary signal that takes a value of High or Low. The optical signal transmission unit 133 is configured to be able to execute a data signal transmission process only when the value of the TxDisable signal is Low. That is, the optical signal transmission unit 133 is configured to be able to execute a data signal transmission process when the value of the TxDisable signal is Low, and is configured to be unable to execute a data signal transmission process when the value of the TxDisable signal is High. Therefore, the control unit 135 can permit the optical signal transmission unit 133 to execute a data signal transmission process by setting the value of the TxDisable signal to Low. Furthermore, the control unit 135 can prohibit the optical signal transmission unit 133 from executing a data signal transmission process by setting the value of the TxDisable signal to High.

[0025] As will be described later, control of the optical signal transmission unit 133 using the TxDisable signal can also be used to generate a short pulse signal, which is a test signal. In this case, the control unit 135 periodically switches the value of the TxDisable signal provided to the optical signal transmission unit 133. The optical signal transmission unit 133 generates a short pulse signal, which is an optical signal that is turned OFF when the value of the TxDisable signal acquired from the control unit 135 is High and is turned ON when the value of the TxDisable signal is Low.

[0026] As shown in FIG. 1, the optical receiver 14 includes an optical signal receiving unit 143 and an electrical signal transmitting unit 144.

[0027] The optical signal receiving unit 143 is configured to receive an optical signal from the optical transmitter 13 via the optical communication path 11. The optical signal receiving unit 143 can be realized by, for example, a known optical demodulation circuit. Examples of the optical signal received by the optical signal receiving unit 143 include a data signal, which is an optical signal transmitted by the optical transmitter 13 in the data signal transmission process described above, and a test signal, which is an optical signal transmitted by the optical transmitter 13 in the test signal transmission process described above.

[0028] The electrical signal transmitting unit 144 is configured to transmit an electrical signal to the optical transmitter 13 via the electrical communication path 12. The electrical signal transmitting unit 144 can be realized by, for example, a known electrical modulation circuit. When the electrical signal transmitting unit 144 detects a disruption of the data signal transmitted by the optical transmitter 13 in the above-described data signal transmission process, the electrical signal transmitting unit 144 executes an LOS signal transmission process. The LOS signal transmission process is a process of transmitting an LOS signal, which is an electrical signal, to the optical transmitter 13 via the electrical communication path 12. Furthermore, when the test signal transmitted by the optical transmitter 13 in the above-described test signal transmission process is successfully received, the electrical signal transmitting unit 144 executes a reception confirmation signal transmission process. The reception confirmation signal transmission process is a process of transmitting a reception confirmation signal, which is an electrical signal, to the optical transmitter 13 via the electrical communication path 12.

[0029] The optical transmitter 13 may include an optical signal receiving unit that receives an optical signal, in addition to the optical signal transmitting unit 133 that transmits an optical signal. Similarly, the optical receiver 14 may include an optical signal transmitting unit that transmits an optical signal, in addition to the optical signal receiving unit 143 that receives an optical signal. That is, the optical communication system 1 may be a system that performs one-way optical communication, or a system that performs two-way optical communication. When performing two-way optical communication, two optical fibers may be used as the optical communication path 11. In this case, one optical fiber is used to transmit an optical signal from the optical transmitter 13 to the optical receiver 14, and the other optical fiber is used to transmit an optical signal from the optical receiver 14 to the optical transmitter 13.

[0030] Furthermore, the optical transmitter 13 may include an electrical signal transmitting unit that transmits an electrical signal, in addition to the electrical signal receiving unit 134 that receives an electrical signal. Similarly, the optical receiver 14 may include an electrical signal receiving unit that receives an electrical signal, in addition to the electrical signal transmitting unit 144 that transmits an electrical signal. That is, the optical communication system 1 may be a system that performs one-way electrical communication, or may be a system that performs two-way electrical communication. When performing two-way electrical communication, two metal wires may be used as the electrical communication path 12. In this case, one metal wire is used to transmit an electrical signal from the optical receiver 14 to the optical transmitter 13, and the other metal wire is used to transmit an electrical signal from the optical transmitter 13 to the optical receiver 14.

[0031] (Example of an optical communication system) An in-vehicle video transmission system 1A, which is a specific example of the optical communication system 1, will be described with reference to Fig. 2. Fig. 2 is a block diagram showing the configuration of the in-vehicle video transmission system 1A.

[0032] In the in-vehicle video transmission system 1A, the optical communication path 11 is an optical fiber housed in an optical cable, and the electrical communication path 12 is a metal wire housed in an electrical cable. The optical cable that houses the optical communication path 11 and the electrical cable that houses the electrical communication path 12 are bundled together. That is, the optical cable that houses the optical communication path 11 and the electrical cable that houses the electrical communication path 12 form a harness. Also, in the in-vehicle video transmission system 1A, the optical transmitter 13 is a camera, and the optical receiver 14 is an ECU (Electronic Control Unit).

[0033] The optical transmitter 13, which is a camera, includes an optical connector 131, an electrical connector 132, an optical signal transmitting unit 133, an electrical signal receiving unit 134, and a control unit 135, as well as an image sensor 136. The image sensor 136 generates a video signal and provides it to the optical signal transmitting unit 133. The data signal transmitted by the optical signal transmitting unit 133 in the data signal transmission process described above is the video signal generated by the image sensor 136.

[0034] The optical receiver 14, which is an ECU, includes a processor 145 in addition to an optical connector 141, an electrical connector 142, an optical signal receiving unit 143, and an electrical signal transmitting unit 144. When the processor 145 detects a disruption of the data signal by monitoring the LOS line of the optical signal receiving unit 143, it generates an LOS signal and provides it to the electrical signal transmitting unit 144. The LOS signal transmitted by the electrical signal transmitting unit 144 in the above-described LOS signal transmission process is the LOS signal generated by the processor 145. Furthermore, when the processor 145 detects reception of a test signal by monitoring the signal line of the optical signal receiving unit 143, it generates a reception confirmation signal and provides it to the electrical signal transmitting unit 144. The reception confirmation signal transmitted by the electrical signal transmitting unit 144 in the above-described reception confirmation transmission process is the reception confirmation signal generated by the processor 145.

[0035] It should be noted here that the optical transmitter 13 and the optical receiver 14 do not have a high-performance communication interface such as I2C in the optical communication system 1. As will be described later, the optical communication system 1 has a function to prevent signal light from entering the eyes of an operator who mates or detaches an optical connector, but it is noteworthy that such a function is realized without relying on a high-performance communication interface such as I2C.

[0036] The optical communication system 1 can also be realized as an AOC (Active Optical Cable) for connecting a camera and an ECU. In this case, the optical communication path 11 is an optical fiber, the electrical communication path 12 is a metal wire, the optical transmitter 13 is a camera-side connector connected to the camera, and the optical receiver 14 is an ECU-side connector connected to the ECU.

[0037] In this case, in a data signal transmission process, the optical signal transmission unit 133 built into the camera-side connector transmits an optical signal representing a video signal acquired from an image sensor built into the camera to the optical receiver 14, which is an ECU-side connector, via the optical communication path 11, which is an optical fiber. Also, in this case, in an LOS signal transmission process, the electrical signal transmission unit 144 built into the ECU-side connector transmits an electrical signal representing an LOS signal acquired from a processor built into the ECU to the optical transmitter 13, which is a camera-side connector, via the electrical communication path 12, which is a metal wire. Also, in a reception confirmation signal transmission process, the electrical signal transmission unit 144 built into the ECU-side connector transmits an electrical signal representing a reception confirmation signal acquired from the processor built into the ECU to the optical transmitter 13, which is a camera-side connector, via the electrical communication path 12, which is a metal wire.

[0038] (Optical transmitter operation) The optical communication path 11 includes optical connectors 11c and 11d. Therefore, if the optical connectors 11c and 11d are disengaged, there is a risk that a strong optical data signal may be incident on the eyes of a worker performing the mating or unmating work of the optical connectors 11c and 11d. A similar risk exists when the optical connectors 11a and 131 are disengaged, and when the optical connectors 11b and 141 are disengaged. Below, we will explain the operation of the optical transmitter 13 when communication starts and when communication resumes. The operation of the optical transmitter 13 described below is intended to reduce this risk, that is, to achieve eye safety.

[0039] (Optical transmitter operation at the start of communication) The operation of the optical transmitter 13 at the start of communication will be described with reference to Fig. 3. Fig. 3 is a flow diagram showing the flow of the operation of the optical transmitter 13 at the start of communication.

[0040] The optical transmitter 13 first executes a first inhibition process S11. The first inhibition process S11 is a process for inhibiting the execution of a data signal transmission process by the optical signal transmission unit 133. The first inhibition process S11 is realized, for example, by setting the value of the TxDisable signal supplied by the control unit 135 to the optical signal transmission unit 133 to High.

[0041] Upon completing the first prohibition process S11, the optical transmitter 13 executes a first test signal transmission process S12 (an example of the "first test signal transmission process" in the claims). The first test signal transmission process S12 is a process of transmitting a first test signal, which is an optical signal having a lower power than the data signal, to the optical receiver 14 via the optical communication path 11. The first test signal transmission process S12 is realized, for example, by the optical signal transmitter 133 performing short pulse oscillation.

[0042] The optical receiver 14 executes a first reception confirmation signal transmission process (an example of a "first control signal transmission process" in the claims) when it has successfully received the first test signal transmitted from the optical transmitter 13. The first reception confirmation signal transmission process is a process of transmitting a first reception confirmation signal, which is an electrical signal indicating that the first test signal has been successfully received, to the optical transmitter 13 via the electrical communication path 12.

[0043] The optical transmitter 13 repeats the first test signal transmission process S12 until it successfully receives the first reception acknowledgment signal transmitted from the optical receiver 14. When the optical transmitter 13 successfully receives the first reception acknowledgment signal transmitted from the optical receiver 14, it executes a first permission process S13. The first permission process S13 is a process for permitting the optical signal transmission unit 133 to execute a data signal transmission process. The first permission process S13 is realized, for example, by setting the value of the TxDisable signal supplied by the control unit 135 to Low.

[0044] When the first permission process S13 is executed, the optical transmitter 13 executes a first data signal transmission process S14 (an example of a "data signal transmission process" in the claims). The first data signal transmission process S14 is a process of transmitting a data signal, which is an optical signal, to the optical receiver 14 via the optical communication path 11. The first data signal transmission process S14 is realized, for example, by the optical signal transmitter 133 converting a data signal (e.g., video data) acquired from a signal source (e.g., an image sensor) into an optical signal and transmitting the optical signal.

[0045] When the optical transmitter 13 is operated as described above, the first data signal transmission process S14 is executed only when an optical connection between the optical transmitter 13 and the optical receiver 14 via the optical communication path 11 is established and an electrical connection between the optical transmitter 13 and the optical receiver 14 via the electrical communication path 12 is established. This is because if an optical connection between the optical transmitter 13 and the optical receiver 14 is not established, the optical receiver 14 will not succeed in receiving the first test signal, and if an electrical connection between the optical transmitter 13 and the optical receiver 14 is not established, the optical transmitter 13 will not succeed in receiving the first acknowledgement signal.

[0046] Below, we will explain (1) the effect of limiting the start of execution of the first data signal transmission process S14 to when an electrical connection between the optical transmitter 13 and the optical receiver 14 is established, and (2) the effect of limiting the start of execution of the first data signal transmission process S14 to when an optical connection between the optical transmitter 13 and the optical receiver 14 is established.

[0047] (1) The effect of limiting the scope to cases where an electrical connection is established It is conceivable that an unmating operation may be started during execution of the first data signal transmission process S14. Here, the unmating operation refers to the operation of unmating the optical connectors 11c and 11d, the optical connectors 11a and 131, or the optical connectors 11b and 142. If the unmating operation is started during execution of the first data signal transmission process S14, there is a risk that the data signal, which is a strong optical signal, may be incident on the eyes of the worker performing the unmating operation.

[0048] For this reason, the optical receiver 14 is configured to execute the above-described LOS signal transmission process when it detects a disruption of the data signal transmitted by the optical transmitter 13 in the first data signal transmission process S14. Furthermore, the optical transmitter 13 is configured to stop or suspend the execution of the first data signal transmission process S14 when it receives an LOS signal while executing the first data signal transmission process S14. This reduces the risk of the data signal, which is a strong optical signal, being incident on the eyes of the worker performing the disassembly work.

[0049] However, if the electrical connectors 12c, 12d, 12a, 132, or 12b, 143 (hereinafter simply referred to as "electrical connectors") are disengaged when the unmating operation is started, the optical transmitter 13 cannot receive the LOS signal, and as a result, the execution of the first data signal transmission process S14 cannot be stopped or interrupted. Therefore, it is not possible to reduce the risk of the data signal, which is a strong optical signal, being incident on the eyes of the worker performing the unmating operation.

[0050] For this reason, in the optical communication system 1 according to this embodiment, the start of the first data signal transmission process S14 is limited to when an electrical connection has been established between the optical transmitter 13 and the optical receiver 14. This reduces the possibility that the electrical connectors will be disengaged when the unmating operation is started during the execution of the first data signal transmission process S14. As a result, it reduces the risk that the data signal, which is a strong optical signal, will be incident on the eyes of the worker performing the unmating operation when the unmating operation is started during the execution of the first data signal transmission process S14.

[0051] (2) The effect of limiting the scope to cases where an optical connection is established It is conceivable that the first data signal transmission process S14 may be started while a mating operation is being performed. Here, the mating operation refers to the operation of mating the optical connectors 11c and 11d, the optical connectors 11a and 131, or the optical connectors 11b and 142. If the first data signal transmission process S14 is started while a mating operation is being performed, there is a risk that the data signal, which is a strong optical signal, may be incident on the eyes of the worker performing the mating operation.

[0052] For this reason, in the optical communication system 1 according to this embodiment, the start of the first data signal transmission process S14 is limited to when an optical connection is established between the optical transmitter 13 and the optical receiver 14. This eliminates the possibility that the first data signal transmission process S14 will be started while a mating operation is being performed. As a result, it is possible to eliminate the risk of a data signal, which is a strong optical signal, being incident on the eyes of a worker performing the mating operation.

[0053] In the optical communication system 1 according to this embodiment, it is not possible to eliminate the possibility that the first test signal transmission process S12 will be started while the mating work is being performed. However, the first test signal transmitted from the optical transmitter 13 in the first test signal transmission process S12 is an optical signal with lower power than the data signal. Therefore, even if the first test signal is incident on the eyes of the worker performing the mating work, it will not cause any damage to the eyes of the worker performing the mating work.

[0054] Although a test signal transmitted by the optical transmitter 13 and a reception confirmation signal transmitted by the optical receiver 14 are used here to check the optical and electrical connection between the optical transmitter 13 and the optical receiver 14, the present invention is not limited to this. For example, a Link Integrity Test defined in IEEE802.3 may be used to check the electrical connection between the optical transmitter 13 and the optical receiver 14.

[0055] (Modification of the operation of the optical transmitter at the start of communication) A modified example of the operation of the optical transmitter 13 at the start of communication will be described with reference to Fig. 4. Fig. 4 is a flow chart showing the flow of the operation of the optical transmitter 13 at the start of communication according to this modified example.

[0056] 4 is the operation of the optical transmitter 13 shown in FIG. 3 with the addition of a first determination process S15 for determining whether the optical transmitter 13 and the optical receiver 14 are electrically connected via the electrical communication path 12. As an example, after transmitting a matching confirmation frame to the optical receiver 14 via the electrical communication path 12, if the optical transmitter 13 succeeds in arbitration and receives a reply (ACK) from the optical receiver 14 in response to the matching confirmation frame, the optical transmitter 13 determines that they are connected; otherwise, the optical transmitter 13 determines that they are not connected. The first test signal transmission process S12 is performed only when it is determined that the optical transmitter 13 and the optical receiver 14 are electrically connected via the electrical communication path 12.

[0057] In the operation of the optical transmitter 13 shown in Fig. 3, if the optical transmitter 13 and the optical receiver 14 are not electrically connected via the electrical communication path 12, the first test signal transmission process S12 is repeated endlessly. This is because the optical transmitter 13 cannot receive the first reception confirmation signal even if the optical receiver 14 transmits the first reception confirmation signal. In contrast, in the operation of the optical transmitter 13 shown in Fig. 4, the first test signal transmission process S12 is executed only when the optical transmitter 13 and the optical receiver 14 are electrically connected via the electrical communication path 12. This makes it possible to prevent the first test signal transmission process S12 from being repeated endlessly for the above-mentioned reason.

[0058] (Optical transmitter operation after communication is interrupted) The operation of the optical transmitter 13 after communication is interrupted will be described with reference to Fig. 5. Fig. 5 is a flow diagram showing the flow of the operation of the optical transmitter 13 after communication is interrupted.

[0059] As described above, when the optical receiver 14 detects a disruption of the data signal transmitted by the optical transmitter 13 in the first data signal transmission process S14, it executes an LOS signal transmission process (an example of the "second control signal transmission process" in the claims) to transmit an LOS signal, which is an electrical signal, to the optical transmitter 13 via the electrical communication path 12.

[0060] When the optical transmitter 13 receives the LOS signal transmitted from the optical receiver 14, it executes a second inhibition process S21. The second inhibition process S21 is a process for inhibiting the optical signal transmission unit 133 from executing a data signal transmission process. The second inhibition process S21 is realized, for example, by the control unit 135 setting the value of the TxDisable signal supplied to the optical signal transmission unit 133 to High. When the value of the TxDisable signal is changed to High, the optical transmitter 13 stops or interrupts the first data signal transmission process S14.

[0061] Upon completing the second prohibition process S21, the optical transmitter 13 executes a second test signal transmission process S22 (an example of the "second test signal transmission process" in the claims). The second test signal transmission process S22 is a process of transmitting a second test signal, which is an optical signal having a lower power than the data signal, to the optical receiver 14 via the optical communication path 11. The second test signal transmission process S22 is realized, for example, by the optical signal transmitter 133 performing short pulse oscillation.

[0062] The optical receiver 14 executes a second reception confirmation signal transmission process (an example of a "third control signal transmission process" in the claims) when it has successfully received the second test signal transmitted from the optical transmitter 13. The second reception confirmation signal transmission process is a process of transmitting a second reception confirmation signal, which is an electrical signal indicating that the second test signal has been successfully received, to the optical transmitter 13 via the electrical communication path 12.

[0063] The optical transmitter 13 repeats the second test signal transmission process S22 until it successfully receives the second reception acknowledgment signal transmitted from the optical receiver 14. When the optical transmitter 13 successfully receives the second reception acknowledgment signal transmitted from the optical receiver 14, it executes the second permission process S23. The second permission process S23 is a process for permitting the optical signal transmission unit 133 to execute the data signal transmission process. The second permission process S23 is realized, for example, by the control unit 135 setting the value of the TxDisable signal supplied to the optical signal transmission unit 133 to Low.

[0064] When the second permission process S23 is executed, the optical transmitter 13 executes a second data signal transmission process S24 (an example of a "data signal transmission process" in the claims). The second data signal transmission process S24 is a process of transmitting a data signal, which is an optical signal, to the optical receiver 14 via the optical communication path 11. The data signal transmitted in the second data signal transmission process S24 may be an untransmitted portion of the data signal whose transmission was interrupted in the first data signal transmission process S14, or may be a new data signal different from the data signal whose transmission was stopped in the first data signal transmission process S14. In the former case, the start of the second data signal transmission process S24 can be regarded as a restart of the first data signal transmission process S14.

[0065] When the optical transmitter 13 is operated as described above, the second data signal transmission process S24 is executed only when an optical connection between the optical transmitter 13 and the optical receiver 14 via the optical communication path 11 is established and an electrical connection between the optical transmitter 13 and the optical receiver 14 via the electrical communication path 12 is established. This is because if an optical connection between the optical transmitter 13 and the optical receiver 14 is not established, the optical receiver 14 will not succeed in receiving the second test signal, and if an electrical connection between the optical transmitter 13 and the optical receiver 14 is not established, the optical transmitter 13 will not succeed in receiving the second acknowledgement signal.

[0066] Below, we will explain (1) the effect of limiting the start of execution of the second data signal transmission process S24 to when an electrical connection between the optical transmitter 13 and the optical receiver 14 is established, and (2) the effect of limiting the start of execution of the second data signal transmission process S24 to when an optical connection between the optical transmitter 13 and the optical receiver 14 is established.

[0067] (1) The effect of limiting the scope to cases where an electrical connection is established It is conceivable that the disengagement work may be started while the second data signal transmission process S24 is being executed. If the disengagement work is started while the second data signal transmission process S24 is being executed, there is a risk that the data signal, which is a strong optical signal, may be incident on the eyes of the worker performing the disengagement work.

[0068] For this reason, the optical receiver 14 is configured to execute the above-mentioned LOS signal transmission process when it detects a disruption of the data signal transmitted by the optical transmitter 13 in the second data signal transmission process S24. Furthermore, the optical transmitter 13 is configured to stop or suspend the execution of the second data signal transmission process S24 when it receives an LOS signal while executing the second data signal transmission process S24. This reduces the risk of the data signal, which is a strong optical signal, being incident on the eyes of the worker performing the disassembly work.

[0069] However, if the electrical connector is disengaged when the unmating operation is started, the optical transmitter 13 cannot receive the LOS signal, and as a result, the execution of the second data signal transmission process S24 cannot be stopped or interrupted, which makes it impossible to reduce the risk of the data signal, which is a strong optical signal, being incident on the eyes of the worker performing the unmating operation.

[0070] For this reason, in the optical communication system 1 according to this embodiment, the start of the second data signal transmission process S24 is limited to when an electrical connection has been established between the optical transmitter 13 and the optical receiver 14. This reduces the possibility that the electrical connectors will be disengaged when the unmating operation is started during the execution of the second data signal transmission process S24. As a result, it reduces the risk that the data signal, which is a strong optical signal, will be incident on the eyes of the worker performing the unmating operation when the unmating operation is started during the execution of the second data signal transmission process S24.

[0071] (2) The effect of limiting the scope to cases where an optical connection is established It is conceivable that the second data signal transmission process S24 may be started during the execution of the joining work. If the second data signal transmission process S24 is started during the execution of the joining work, there is a risk that the data signal, which is a strong optical signal, may be incident on the eyes of the worker performing the joining work.

[0072] For this reason, in the optical communication system 1 according to this embodiment, the second data signal transmission process S24 is started only when an optical connection is established between the optical transmitter 13 and the optical receiver 14. This eliminates the possibility that the second data signal transmission process S24 will be started while a mating operation is being performed. As a result, it is possible to eliminate the risk of a data signal, which is a strong optical signal, being incident on the eyes of a worker performing the mating operation.

[0073] In the optical communication system 1 according to this embodiment, it is not possible to eliminate the possibility that the second test signal transmission process S22 will be started while the mating work is being performed. However, the second test signal transmitted from the optical transmitter 13 in the second test signal transmission process S22 is an optical signal with a lower power than the data signal. Therefore, even if the second test signal is incident on the eyes of the worker performing the mating work, it will not cause any damage to the eyes of the worker performing the mating work.

[0074] Although a test signal transmitted by the optical transmitter 13 and a reception confirmation signal transmitted by the optical receiver 14 are used here to check the optical and electrical connection between the optical transmitter 13 and the optical receiver 14, the present invention is not limited to this. For example, a Link Test defined in IEEE802.3 may be used to check the electrical connection between the optical transmitter 13 and the optical receiver 14.

[0075] (Modification of the operation of the optical transmitter after communication is interrupted) A modified example of the operation of the optical transmitter 13 after communication is interrupted will be described with reference to Fig. 6. Fig. 6 is a flow chart showing the flow of the operation of the optical transmitter 13 after communication is interrupted according to this modified example.

[0076] 6 is the operation of the optical transmitter 13 shown in FIG. 5 with the addition of a second determination process S25 for determining whether the optical transmitter 13 and the optical receiver 14 are electrically connected via the electrical communication path 12. As an example, after transmitting a matching confirmation frame to the optical receiver 14 via the electrical communication path 12, if the optical transmitter 13 succeeds in arbitration and receives a reply (ACK) from the optical receiver 14 in response to the matching confirmation frame, the optical transmitter 13 determines that they are electrically connected; otherwise, the optical transmitter 13 determines that they are not electrically connected. The second test signal transmission process S22 is performed only when it is determined that the optical transmitter 13 and the optical receiver 14 are electrically connected via the electrical communication path 12.

[0077] In the operation of the optical transmitter 13 shown in Fig. 5, if the optical transmitter 13 and the optical receiver 14 are not electrically connected via the electrical communication path 12, the second test signal transmission process S22 is repeated endlessly. This is because the optical transmitter 13 cannot receive the second reception confirmation signal even if the optical receiver 14 transmits the second reception confirmation signal. In contrast, in the operation of the optical transmitter 13 shown in Fig. 6, the second test signal transmission process S22 is executed only when the optical transmitter 13 and the optical receiver 14 are electrically connected via the electrical communication path 12. This makes it possible to prevent the second test signal transmission process S22 from being repeated endlessly for the above-mentioned reason.

[0078] (A secondary effect of optical communication systems) Unlike electrical communications, optical communications typically do not produce electromagnetic wave leakage, so it is expected that eavesdropping will be attempted by unmating the optical connector and directly observing the optical signal. In contrast, in the optical communication system 1 according to this embodiment, unmating the optical connector stops the transmission of the optical signal from the optical transmitter 13. This makes it possible to prevent eavesdropping on the optical signal.

[0079] (Use of composite cables) The optical transmitter 13 and the optical receiver 14 may be connected using two cables, i.e., an optical cable containing the optical communication path 11 and an electrical cable containing the electrical communication path 12, or may be connected using one cable, i.e., a composite cable containing the optical communication path 11 and the electrical communication path 12.

[0080] An example of a composite cable accommodating an optical communication path 11 and an electrical communication path 12 is shown in Fig. 7. Fig. 7 is a cross-sectional view showing a transverse section of a composite cable 10 accommodating an optical communication path 11 and an electrical communication path 12. The composite cable 10 shown in Fig. 7 is a composite cable suitable for cases where two-way optical communication is possible. In other words, it is a composite cable suitable for cases where the optical transmitter 13 has the function of receiving an optical signal in addition to the function of transmitting an optical signal, and the optical receiver 14 has the function of transmitting an optical signal in addition to the function of receiving an optical signal.

[0081] The composite cable 10 shown in Figure 7 includes two optical fibers 111 and 112 that function as the optical communication path 11 and two metal wires 121 and 122 that function as the electrical communication path 12. One of the two optical fibers 111 and 112 is used to transmit an optical signal transmitted from an optical transmitter 13 to an optical receiver 14, and the other of the two optical fibers 111 and 112 is used to transmit an optical signal transmitted from the optical receiver 14 to the optical transmitter 13. The two metal wires 121 and 122 are twisted together to form a differential signal line. The two metal wires 121 and 122 are used to transmit an electrical signal transmitted from the optical receiver 14 to the optical transmitter 13 and to transmit an electrical signal transmitted from the optical transmitter 13 to the optical receiver 14.

[0082] A composite connector that simultaneously realizes optical and electrical connection is used to connect the composite cable 10 and the optical transmitter 13, and to connect the composite cable 10 and the optical receiver 14. The same applies to connecting two composite cables 10 together. For this reason, when using the composite cable 10, it is more difficult to achieve a state in which the optical transmitter 13 and the optical receiver 14 are optically connected via the optical communication path 11 but are not electrically connected via the electrical communication path 12, compared to when two cables are used.

[0083] However, if the metal wires 121, 122 inside the composite cable 10 are broken or if an electrical circuit inside the composite connector fails, the above situation can occur. Therefore, even when the optical transmitter 13 and the optical receiver 14 are connected using a single cable (composite cable 10), there is a risk that a data signal, which is a strong optical signal, may be incident on the eyes of a worker performing the mating or unmating work, just as there is when the optical transmitter 13 and the optical receiver 14 are connected using two cables (an optical cable and an electrical cable). Therefore, even when the optical transmitter 13 and the optical receiver 14 are connected using a single cable, there is an effect of reducing the risk that a data signal, which is a strong optical signal, may be incident on the eyes of a worker performing the mating or unmating work, just as there is when the optical transmitter 13 and the optical receiver 14 are connected using two cables.

[0084] (Additional information) In vehicle control such as autonomous driving, an ECU controls various parts of the vehicle based on video signals acquired from a camera. If an abnormality occurs in an in-vehicle video transmission system used to acquire the video signals, it is preferable for the ECU to control the vehicle to a safe state, such as by stopping the vehicle. However, if an abnormality occurs in which the electrical connection between the camera and the ECU is cut off without cutting off the optical connection between the camera and the ECU, the ECU cannot recognize the occurrence of the abnormality as long as the transmission of the video signals from the camera to the ECU continues, and as a result, the ECU cannot control the vehicle to a safe state.

[0085] Such problems can be solved by using an in-vehicle video transmission system 1A, which is a specific example of the optical communication system 1. That is, the camera (optical transmitter 13) included in the in-vehicle video transmission system 1A transmits a video signal only when an electrical connection is established between the camera (optical transmitter 13) and the ECU (optical receiver 14). Therefore, if an abnormal event occurs in which the electrical connection between the camera (optical transmitter 13) and the ECU (optical receiver 14) is cut off, the ECU (optical receiver 14) can recognize the occurrence of this abnormal event by the interruption of the video signal, and both can control the vehicle to a safe state.

[0086] (summary) An optical communication system according to aspect 1 of the present invention includes an optical communication path, an electrical communication path, an optical receiver optically connected to one end of the optical communication path and electrically connected to one end of the electrical communication path, and an optical transmitter optically connected to the other end of the optical communication path and electrically connected to the other end of the electrical communication path, and is characterized in that the optical transmitter performs a data signal transmission process of transmitting a data signal, which is an optical signal, to the optical receiver via the optical communication path only when the optical transmitter is electrically connected to the optical receiver via the electrical communication path.

[0087] An optical communication system according to aspect 2 of the present invention is an optical communication system according to aspect 1, characterized in that the optical transmitter executes a first test signal transmission process to transmit a first test signal, which is an optical signal having lower power than the data signal, to the optical receiver via the optical communication path, and if the optical receiver successfully receives the first test signal, executes a first control signal transmission process to transmit a first control signal, which is an electrical signal, to the optical transmitter via the electrical communication path, and if the optical transmitter successfully receives the first control signal, starts the data signal transmission process.

[0088] An optical communication system according to aspect 3 of the present invention is an optical communication system according to aspect 2, characterized in that the optical transmitter starts the first test signal transmission process only when it is electrically connected to the optical receiver via the electrical communication path.

[0089] An optical communication system according to aspect 4 of the present invention is an optical communication system according to aspect 2, characterized in that, when the optical receiver fails to receive the data signal, it executes a second control signal transmission process to transmit a second control signal, which is an electrical signal, to the optical transmitter via the electrical communication path, and when the optical transmitter receives the second control signal, it cancels or interrupts the data signal transmission process.

[0090] An optical communication system according to aspect 5 of the present invention is an optical communication system according to aspect 4, characterized in that, after stopping the data signal transmission process, the optical transmitter executes a second test signal transmission process to transmit a second test signal, which is an optical signal having lower power than the data signal, to the optical receiver via the optical communication path, and if the optical receiver successfully receives the second test signal, it executes a third control signal transmission process to transmit a third control signal, which is an electrical signal, to the optical transmitter via the electrical communication path, and if the optical transmitter successfully receives the third control signal, it starts or resumes the data signal transmission process.

[0091] An optical communication system according to aspect 6 of the present invention is an optical communication system according to aspect 5, characterized in that the optical transmitter starts or resumes the second test signal transmission process only when it is electrically connected to the optical receiver via the electrical communication path.

[0092] An optical communication system according to aspect 7 of the present invention is an optical communication system according to any one of aspects 1 to 6, characterized in that the optical communication path is divided into a first section on the optical transmitter side and a second section on the optical receiver side, and a first optical connector provided at the end of the first section on the optical receiver side and a second optical connector provided at the end of the second section on the optical transmitter side are configured to be detachable.

[0093] An optical communication system according to aspect 8 of the present invention is an optical communication system according to any one of aspects 1 to 6, characterized in that the electrical communication path is divided into a first section on the optical transmitter side and a second section on the optical receiver side, and a first electrical connector provided at the end of the first section on the optical receiver side and a second electrical connector provided at the end of the second section on the optical transmitter side are configured to be detachable.

[0094] An optical communication system according to aspect 9 of the present invention is an optical communication system according to any one of aspects 1 to 6, characterized in that the optical communication path is an optical fiber included in a composite cable, and the electrical communication path is a metal wire included in the composite cable.

[0095] An optical communication system according to aspect 10 of the present invention is an optical communication system according to any one of aspects 1 to 6, characterized in that the optical transmitter is built into or connected to a camera, and the data signal is a data signal representing an image or video captured by the camera.

[0096] An optical communication method according to aspect 11 of the present invention is an optical communication method in an optical communication system including an optical receiver optically connected to one end of an optical communication path and electrically connected to one end of an electrical communication path, and an optical transmitter optically connected to the other end of the optical communication path and electrically connected to the other end of the electrical communication path, characterized in that a data signal transmission process is executed to transmit a data signal, which is an optical signal, from the optical transmitter to the optical receiver via the optical communication path only when the optical transmitter and the optical receiver are electrically connected via the electrical communication path.

[0097] The optical transmitter according to aspect 12 of the present invention is an optical transmitter that is optically connected to one end of an optical communication path to which an optical receiver is optically connected, and is electrically connected to the other end of an electrical communication path to which the optical receiver is electrically connected at one point, and is characterized in that it performs a data signal transmission process of transmitting a data signal, which is an optical signal, to the optical receiver via the optical communication path only when it is electrically connected to the optical receiver via the electrical communication path.

[0098] (Additional notes) The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in the above-described embodiments are also included in the technical scope of the present invention. [Explanation of symbols]

[0099] 1 Optical communication systems 11 Optical communication path 12 Telecommunications Channels 13 Optical transmitter 14 Optical receiver

Claims

1. an optical communication system including an optical communication path, an electrical communication path, an optical receiver optically connected to one end of the optical communication path and electrically connected to one end of the electrical communication path, and an optical transmitter optically connected to the other end of the optical communication path and electrically connected to the other end of the electrical communication path, the optical transmitter performing a data signal transmission process of transmitting a data signal, which is an optical signal, to the optical receiver via the optical communication path only when the optical transmitter is electrically connected to the optical receiver via the electrical communication path, the optical transmitter executes a first test signal transmission process of transmitting a first test signal, which is an optical signal having a lower power than the data signal, to the optical receiver via the optical communication path; If the optical receiver has successfully received the first test signal, the optical receiver executes a first control signal transmission process of transmitting a first control signal, which is an electrical signal, to the optical transmitter via the electrical communication path; the optical transmitter starts the data signal transmission process when the first control signal is successfully received; Optical communication system.

2. the optical transmitter starts the first test signal transmission process only when electrically connected to the optical receiver via the electrical communication path; 2. The optical communication system according to claim 1.

3. when the optical receiver fails to receive the data signal, it executes a second control signal transmission process of transmitting a second control signal, which is an electrical signal, to the optical transmitter via the electrical communication path; When the optical transmitter receives the second control signal, the optical transmitter stops or suspends the data signal transmission process.

2. The optical communication system according to claim 1.

4. the optical transmitter, after stopping the data signal transmission process, executes a second test signal transmission process of transmitting a second test signal, which is an optical signal having a lower power than the data signal, to the optical receiver via the optical communication path; if the optical receiver has successfully received the second test signal, it executes a third control signal transmission process of transmitting a third control signal, which is an electrical signal, to the optical transmitter via the electrical communication path; When the optical transmitter has successfully received the third control signal, the optical transmitter starts or resumes the data signal transmission process.

4. The optical communication system according to claim 3.

5. the optical transmitter starts or resumes the second test signal transmission process only when the optical transmitter is electrically connected to the optical receiver via the electrical communication path; 5. The optical communication system according to claim 4.

6. an optical communication system including an optical communication path, an electrical communication path, an optical receiver optically connected to one end of the optical communication path and electrically connected to one end of the electrical communication path, and an optical transmitter optically connected to the other end of the optical communication path and electrically connected to the other end of the electrical communication path, the optical transmitter performing a data signal transmission process of transmitting a data signal, which is an optical signal, to the optical receiver via the optical communication path only when the optical transmitter is electrically connected to the optical receiver via the electrical communication path, when the optical receiver fails to receive the data signal, it executes a second control signal transmission process of transmitting a second control signal, which is an electrical signal, to the optical transmitter via the electrical communication path; When the optical transmitter receives the second control signal, the optical transmitter stops or suspends the data signal transmission process. Optical communication system.

7. the optical communication path is divided into a first section on the optical transmitter side and a second section on the optical receiver side, a first optical connector provided at an end of the first section on the optical receiver side and a second optical connector provided at an end of the second section on the optical transmitter side are configured to be detachable; 7. An optical communication system according to claim 1.

8. the electrical communication path is divided into a first section on the optical transmitter side and a second section on the optical receiver side, a first electrical connector provided at an end of the first section on the optical receiver side and a second electrical connector provided at an end of the second section on the optical transmitter side are configured to be detachable; 7. An optical communication system according to claim 1.

9. the optical communication path is an optical fiber included in a composite cable, The electrical communication path is a metal wire included in the composite cable.

7. An optical communication system according to claim 1.

10. The optical transmitter is built into or connected to a camera, The data signal is a data signal representing an image or video captured by the camera.

7. An optical communication system according to claim 1.

11. An optical communication method in an optical communication system including an optical receiver optically connected to one end of an optical communication path and electrically connected to one end of an electrical communication path, and an optical transmitter optically connected to the other end of the optical communication path and electrically connected to the other end of the electrical communication path, the optical transmitter performing a data signal transmission process for transmitting a data signal, which is an optical signal, to the optical receiver via the optical communication path only when the optical transmitter is electrically connected to the optical receiver via the electrical communication path, the optical transmitter executes a first test signal transmission process of transmitting a first test signal, which is an optical signal having a lower power than the data signal, to the optical receiver via the optical communication path; If the optical receiver has successfully received the first test signal, the optical receiver executes a first control signal transmission process of transmitting a first control signal, which is an electrical signal, to the optical transmitter via the electrical communication path; the optical transmitter starts the data signal transmission process when the first control signal is successfully received; Optical communication method.

12. An optical transmitter is optically connected to one end of an optical communication path, the other end of which is optically connected to an optical receiver, and is electrically connected to the other end of an electrical communication path, the other end of which is electrically connected to the optical receiver, and the optical transmitter performs a data signal transmission process of transmitting a data signal, which is an optical signal, to the optical receiver via the optical communication path only when the optical transmitter is electrically connected to the optical receiver via the electrical communication path, the optical transmitter executes a first test signal transmission process of transmitting a first test signal, which is an optical signal having a lower power than the data signal, to the optical receiver via the optical communication path; If the optical receiver has successfully received the first test signal, the optical receiver executes a first control signal transmission process of transmitting a first control signal, which is an electrical signal, to the optical transmitter via the electrical communication path; the optical transmitter starts the data signal transmission process when the first control signal is successfully received; Optical transmitter.

13. An optical communication method in an optical communication system including an optical receiver optically connected to one end of an optical communication path and electrically connected to one end of an electrical communication path, and an optical transmitter optically connected to the other end of the optical communication path and electrically connected to the other end of the electrical communication path, the optical transmitter performing a data signal transmission process for transmitting a data signal, which is an optical signal, to the optical receiver via the optical communication path only when the optical transmitter is electrically connected to the optical receiver via the electrical communication path, when the optical receiver fails to receive the data signal, it executes a second control signal transmission process of transmitting a second control signal, which is an electrical signal, to the optical transmitter via the electrical communication path; When the optical transmitter receives the second control signal, the optical transmitter stops or suspends the data signal transmission process. Optical communication method.

14. An optical transmitter is optically connected to one end of an optical communication path, the other end of which is optically connected to an optical receiver, and is electrically connected to the other end of an electrical communication path, the other end of which is electrically connected to the optical receiver, and the optical transmitter performs a data signal transmission process of transmitting a data signal, which is an optical signal, to the optical receiver via the optical communication path only when the optical transmitter is electrically connected to the optical receiver via the electrical communication path, when the optical receiver fails to receive the data signal, it executes a second control signal transmission process of transmitting a second control signal, which is an electrical signal, to the optical transmitter via the electrical communication path; When the optical transmitter receives the second control signal, the optical transmitter stops or suspends the data signal transmission process. Optical transmitter.

Images