Communication device, power-feeding device, and communication method

Abstract

Provided is a communication device that is driven by electric power obtained by optical power-feeding and that comprises: a signal processing unit which generates transmission data to be transmitted; and a reflected light control unit which adds the transmission data to reflected light of power-feeding light transmitted from the outside for power-feeding light, and transmits the reflected light with the transmission data to a power-feeding source.　

Description

Communication device, power supply device, and communication method

[0001] The present invention relates to a communication device, a power supply device, and a communication method.

[0002] Conventionally, optical communication systems have been proposed that use optical fibers to supply power from a central office to communication devices and transmit data from the communication devices to the central office (see, for example, Non-Patent Document 1). Fig. 11 is a diagram showing an example of the configuration of a conventional optical communication system S. In the optical communication system S, a central office 1 is equipped with a light source 3 and an optical transceiver 4. The light source 3 outputs light of a certain wavelength as power supply light for supplying power to the communication device 2. The optical transceiver 4 receives an optical signal from the communication device 2.

[0003] The communication device 2 is a communication device powered by power obtained through optical power feeding. The communication device 2 includes a photoelectric conversion unit 5, a power storage unit 6, a signal processing unit 7, and an optical transceiver 8. The photoelectric conversion unit 5 converts the power feeding light transmitted from the light source 3 into electric power. The power storage unit 6 stores the electric power converted by the photoelectric conversion unit 5. The signal processing unit 7 is driven by the electric power stored in the power storage unit 6. The signal processing unit 7 outputs data to be transmitted to the optical transceiver. The optical transceiver 8 converts the data output from the signal processing unit 7 into an optical signal and transmits the converted optical signal to the optical transceiver 4 provided in the station 1 via an optical fiber.

[0004] H. Katsurai, Y. Fukada, R. Miyatake, H. Nagoshi, M. Sekiguchi, and T. Yoshida, 'Sleep / Active operation of optical-power-supplied ONU without electricity for rural IoT', International Conference on Emerging Technologies for Communications(ICETC), 2022.

[0005] Generally, the amount of power that can be supplied by optical fiber is far less than that of a commercial power source. Therefore, even in the conventional configuration, the communication device 2 cannot operate continuously due to the small amount of power it can supply, and instead operates intermittently by alternating between a sleep state with low power consumption and an active state with high power consumption.

[0006] However, the information transmission process using an optical transceiver consumes a large amount of power, particularly in communication devices that use optical transceivers, so there is a demand for technology to further reduce power consumption.

[0007] In view of the above circumstances, an object of the present invention is to provide a technique that can reduce the power consumption of a communication device that is driven by power obtained through optical power feeding.

[0008] One aspect of the present invention is a communication device that is powered by power obtained through optical power supply, and that includes a signal processing unit that generates transmission data to be transmitted, and a reflected light control unit that adds the transmission data to reflected light of the power supply light that is transmitted from outside for the power supply light and transmits the reflected light to the power supply source.

[0009] One aspect of the present invention is a power supply device comprising: a light source that outputs power supply light to be used for optical power supply; a receiving unit that receives transmission data added by a communication device to reflected light of the power supply light generated by reflecting the power supply light in the communication device driven by power obtained by the optical power supply; and a circulator that outputs the power supply light output from the light source to an optical fiber connected to the communication device and outputs reflected light of the power supply light transmitted by the optical fiber connected to the communication device to the receiving unit.

[0010] One aspect of the present invention is a communication method performed by a communication device powered by power obtained through optical power supply, which generates transmission data to be transmitted, adds the transmission data to reflected light of the power supply light transmitted from outside for power supply light, and transmits the data to the power supply source.

[0011] According to the present invention, it is possible to reduce the power consumption of a communication device that is driven by power obtained through optical power feeding.

[0012] FIG. 1 is a diagram showing an example of the configuration of an optical communication system in a first embodiment. FIG. 2 is a diagram showing an example of the configuration of a reflected light control unit that intensity-modulates reflected light in the first embodiment. FIG. 3 is a diagram showing an example of the configuration of a reflected light control unit that intensity-modulates reflected light in the first embodiment. FIG. 4 is a diagram showing an example of binary data transmitted by a reflected light control unit in the first embodiment. FIG. 5 is a diagram showing an example of the configuration of a reflected light control unit that phase-modulates reflected light in the first embodiment. FIG. 6 is a diagram showing an example of the configuration of a reflected light control unit that phase-modulates reflected light in the first embodiment. FIG. 7 is a diagram showing an example of reflected light output from a reflected light control unit 21 in the first embodiment. FIG. 8 is a flowchart showing the flow of data transmission processing performed by a communication device in the first embodiment. FIG. 9 is a diagram showing an example of the configuration of an optical communication system in a second embodiment. FIG. 10 is a flowchart explaining the flow of data transmission processing performed by a communication device in the second embodiment. FIG. 11 is a diagram showing an example of the configuration of a conventional optical communication system.

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0014] 1 is a diagram showing an example of the configuration of an optical communication system 100 according to a first embodiment. The optical communication system 100 includes a power supply device 10 and a communication device 20. The power supply device 10 and the communication device 20 are connected by a single optical fiber.

[0015] The power supply device 10 is provided in a station building and supplies optical power to the communication device 20. Furthermore, the power supply device 10 transmits and receives data to and from the communication device 20.

[0016] The communication device 20 is a device that is driven by power obtained from the power supply light transmitted from the power supply device 10. The power supply light generally has a higher optical intensity than a PON (Passive Optical Network) or the like, and therefore a larger amount of reflected light. Therefore, the communication device 20 in the first embodiment is not an optical transceiver, but adds data to the reflected light and transmits the data to the power supply device 10.

[0017] Next, specific configurations of the power supply device 10 and the communication device 20 will be described. First, the configuration of the power supply device 10 will be described. The power supply device 10 includes a light source 11, an optical transceiver 12, and a circulator 13. The light source 11 outputs light of a certain wavelength as power supply light for supplying power to the communication device 20. The optical transceiver 12 receives an optical signal from the communication device 20.

[0018] The circulator 13 has at least three ports. In the following description, it is assumed that the circulator 13 has three ports. The first port of the circulator 13 is connected to the light source 11. The second port of the circulator 13 is connected to an optical fiber connected to the reflected light control unit 21 in the communication device 20. The third port of the circulator 13 is connected to the optical transceiver 12. An optical signal (feed light) input to the first port of the circulator 13 is output from the second port. An optical signal input to the second port of the circulator 13 is output from the third port. An optical signal input to the third port of the circulator 13 is output from the first port.

[0019] In this way, the power supply device 10 extracts only the reflected light from the optical fiber by using the circulator 13. This allows the power supply device 10 to acquire the transmitted information from the communication device 20.

[0020] Next, the configuration of the communication device 20 will be described. The communication device 20 includes a reflected light control unit 21, a photoelectric conversion unit 22, a power storage unit 23, and a signal processing unit 24. The reflected light control unit 21 adds transmission data output from the signal processing unit 24 to reflected light of power supply light transmitted from the power supply device 10 for power supply light, and transmits the resulting light to the power supply device 10. For example, the reflected light control unit 21 adds the transmission data by modulating the reflected light. The processing performed by the reflected light control unit 21 will be described later.

[0021] The photoelectric conversion unit 22 converts the power supply light transmitted from the light source 11 into electric power. The power storage unit 23 stores the electric power converted by the photoelectric conversion unit 22. The signal processing unit 24 is driven by the electric power stored in the power storage unit 23. The signal processing unit 24 performs predetermined signal processing on the data to be transmitted to generate transmission data. The signal processing unit 24 outputs the generated transmission data to the reflected light control unit 21.

[0022] Next, specific processing by the reflected light control unit 21 in the first embodiment will be described. Methods by which the reflected light control unit 21 modulates the reflected light include intensity modulation and phase modulation. The reflected light control unit 21 may use at least either intensity modulation or phase modulation. Which method to use may be set in advance, may be switched depending on the time period, or may be set by an external instruction.

[0023] (Intensity Modulation of Reflected Light) Any method may be used to control the reflected light, but as a first example, there is a method of switching between a path with a high reflection amount and a path with a low reflection amount using a mechanical optical switch or a MEMS (Micro Electro Mechanical Systems) optical switch. Figures 2 and 3 are diagrams showing an example configuration of the reflected light control unit 21 that intensity modulates the reflected light in the first embodiment. Figures 2 and 3 show a mechanical configuration. When intensity modulating the reflected light, a waveform (e.g., direct current) whose phase and amplitude do not change over time is used as the power supply light.

[0024] 2 and 3, the reflected light control unit 21 includes an input port 211, a plurality of output ports 212-1, and a switching unit 213. In FIGS. 2 and 3, the reflected light control unit 21 includes two output ports 212, but the number of output ports 212 is not particularly limited. The input port 211 is a port into which the power supply light is input. That is, the input port 211 is connected to an optical fiber connected to the power supply device 10. Each of the output ports 212-1 and 212-2 is a port that outputs the power supply light input to the input port 211. A photoelectric conversion unit 22 is connected to at least one of the output ports 212-1 and 212-2. Therefore, the photoelectric conversion unit 22 receives the power supply light output from the output port 212 to which it is connected.

[0025] The switching unit 213 controls the output destination of the power supply light input to the input port 211. The switching unit 213 is composed of a plurality of lenses 214 and a prism 215. A lens 214 is provided for each port, and converts the input light (power supply light) into a parallel beam or focuses the light. The lens 214 is, for example, a GRIN lens. The prism 215 reflects the input light (power supply light) and outputs it to the desired output port 212. The prism 215 is capable of translation. By translating the prism 215, the output destination of the power supply light can be switched between output port 212-1 and output port 212-2.

[0026] Furthermore, the design method for the amount of reflection for each path can be defined, for example, by the number of fusion points. For example, if there are no fusion points P, there will be less reflected light, and if there are fusion points P, there will be more reflected light. The more fusion points P there are, the more reflected light will be. Figures 2 and 3 show a case where output port 212-1 does not have any fusion points P, but output port 212-2 has fusion points P. Therefore, output port 212-2 will reflect more light than output port 212-1.

[0027] Therefore, the reflected light control unit 21 performs intensity modulation by controlling the position of the prism 215 in accordance with the transmission data. For example, when transmitting binary "1" information, the reflected light control unit 21 controls the position of the prism 215 so that light is input to the output port 212-2 having the fusion point P, as shown in Fig. 2. For example, when transmitting binary "0" information, the reflected light control unit 21 controls the position of the prism 215 so that light is input to the output port 212-1 having no fusion point P, as shown in Fig. 3.

[0028] In the above explanation, a configuration in which control is performed based on the presence or absence of fusion points P is shown, but it is also possible that all of the output ports 212 have fusion points P. In such a case, the reflected light control unit 21 can control the position of the prism 215 based on the number of fusion points P. For example, the output port 212 with the most fusion points P may be considered to have a large amount of reflected light, and the output port 212 with the fewest fusion points P may be considered to have a small amount of reflected light.

[0029] FIG. 4 is a diagram showing an example of binary data transmitted by the reflected light control unit 21 in the first embodiment. Consider the case in FIG. 4 where the reflected light control unit 21 transmits binary data "01001." In this case, the reflected light control unit 21 moves the prism 215 to the position of output port 212-1 ( FIG. 3 ) during the period from time t0 to time t1. Next, the reflected light control unit 21 moves the prism 215 to the position of output port 212-2 ( FIG. 2 ) during the period from time t1 to time t2. Next, the reflected light control unit 21 moves the prism 215 to the position of output port 212-1 ( FIG. 3 ) during the period from time t2 to time t4. Then, the reflected light control unit 21 moves the prism 215 to the position of output port 212-2 ( FIG. 2 ) during the period from time t4 to time t5. This enables the transmission of the binary data "01001."

[0030] (Phase Modulation of Reflected Wave) Any method may be used to control the reflected light, but as a second example, there is a method of switching between a path with a long transmission distance and a path with a short transmission distance for the reflected light using a mechanical optical switch or a MEMS optical switch. Figures 5 and 6 are diagrams showing an example configuration of the reflected light control unit 21 that phase modulates the reflected light in the first embodiment. Figures 5 and 6 show a mechanical configuration. When phase modulating the reflected light, a waveform with a time-varying phase (for example, a sine wave) is used as the power supply light.

[0031] As shown in FIGS. 5 and 6 , the reflected light control unit 21 includes an input port 211, multiple output ports 212-1, and a switching unit 213. In FIGS. 5 and 6 , the reflected light control unit 21 includes two output ports 212, but the number of output ports 212 is not particularly limited. Here, in a mechanical optical switch, the state in which output port 212-2 is used is referred to as "switch state 1," and the state in which output port 212-1 is used is referred to as "switch state 2." The transmission distance switching method can be determined, for example, by the location of the fusion point. In FIGS. 5 and 6 , the fusion points of output port 212-1 and output port 212-2 are located at different positions. For example, as viewed from the prism 215, the position of fusion point P1 of output port 212-1 is farther away than the position of fusion point P2 of output port 212-2. For example, in the fiber of output port 212-1, the distance from the light source 11 to fusion point P1 is longer than the fusion point P2 of output port 212-2. Therefore, the transmission distance of output port 212-1 is longer than that of output port 212-2. In this way, the positions of the reflection points (splice points) are shifted between output port 212-1 and output port 212-2. In other words, the optical path length of the reflected light from the reflection point to the light source 11 is made different between output port 212-1 and output port 212-2. As a result, the phase of the reflected wave when it arrives at the light source 11 differs between when it is reflected at output port 212-1 and when it is reflected at output port 212-2.

[0032] Fig. 7 is a diagram showing an example of reflected light output from the reflected light control unit 21 in the first embodiment. Fig. 7 shows reflected light observed at the power supply device 10 (power supply light reflected at a reflection point and returned to the power supply device 10). The upper part of Fig. 7 shows reflected light when the optical switch is always in "switch state 1", the middle part of Fig. 7 shows reflected light when the optical switch is always in "switch state 2", and the lower part of Fig. 7 shows reflected light when the optical switch dynamically switches between "switch state 1" and "switch state 2".

[0033] 7, the distance from the reflection point to the power supply device 10 differs between when the light is reflected within output port 212-1 and when it is reflected within output port 212-2. Therefore, it can be seen that the phase of the reflected light observed at the power supply device 10 also differs. The reflected light control unit 21 utilizes this phenomenon to switch the state of the optical switch according to the transmission data, thereby modulating the phase and transmitting data.

[0034] The lower part of FIG. 7 shows a case where information is transmitted from the communication device 20 to the power supply device 10. For example, a condition that the phase state of the reflected light that first reaches the power supply device 10 is binary "0" is determined in advance between the power supply device 10 and the communication device 20. For example, assume that the phase state of the reflected light when the reflected light control unit 21 is in "switch state 1" (the phase state in the upper part of FIG. 7) is binary "0." Then, when transmitting information of binary "1," the reflected light control unit 21 controls the position of the prism 215 to be in "switch state 2." This changes the phase of the reflected light observed by the power supply device 10. As a result, the power supply device 10 can recognize that the phase has been switched and obtain the information of binary "1."

[0035] Consider the case where the reflected light control unit 21 transmits binary data "0100" based on the above control. In this case, the reflected light control unit 21 moves the prism 215 to the position of output port 212-2 (FIG. 5) so that the switch state is "1" during the period from time t0 to time t1. Next, the reflected light control unit 21 moves the prism 215 to the position of output port 212-1 (FIG. 6) so that the switch state is "2" during the period from time t1 to time t2. Next, the reflected light control unit 21 moves the prism 215 to the position of output port 212-2 (FIG. 5) so that the switch state is "1" during the period from time t2 to time t4. This enables the transmission of binary data "0100".

[0036] Next, the flow of data transmission processing performed by the communication device 20 in the first embodiment will be described. First, the flow of processing by a conventional communication device will be described for comparison with the processing by the communication device 20 in the first embodiment. Here, the description will be given using the communication device 2 shown in FIG. 11 as an example.

[0037] The signal processing unit 7 determines whether there is data to be transmitted. If the signal processing unit 7 determines that there is no data to be transmitted, the signal processing unit 7 waits until data to be transmitted is input. If the signal processing unit 7 determines that there is data to be transmitted, the signal processing unit 7 performs predetermined signal processing on the data to be transmitted to generate transmission data. The signal processing unit 7 outputs the generated transmission data to the optical transceiver 8. The optical transceiver 8 transmits the transmission data output from the signal processing unit 7 via an optical transmission path. At this time, the optical transceiver 8 causes an LED (Light Emitting Diode) to emit light in accordance with the transmission data output from the signal processing unit 7. As a result, the optical transceiver 8 transmits the transmission data by inputting light into the optical transmission path.

[0038] Next, the flow of processing by the communication device 20 in the first embodiment will be described. Fig. 8 is a flowchart showing the flow of data transmission processing performed by the communication device 20 in the first embodiment. It is assumed that power supply light is being transmitted from the power supply device 10 when the processing in Fig. 8 starts. The signal processing unit 24 determines whether there is data to be transmitted (step S101). If the signal processing unit 24 determines that there is no data to be transmitted (step S101-NO), the signal processing unit 24 repeatedly executes the processing of step S101 until data to be transmitted is input.

[0039] If the signal processing unit 24 determines that there is data to be transmitted (step S101—YES), the signal processing unit 24 performs predetermined signal processing on the data to be transmitted to generate transmission data. The signal processing unit 24 outputs the generated transmission data to the reflected light control unit 21. The reflected light control unit 21 adds the transmission data to the reflected light in accordance with the transmission data output from the signal processing unit 24 and transmits the data (step S102).

[0040] According to the optical communication system 100 configured as described above, the communication device 20 includes a signal processing unit 24 that generates transmission data to be transmitted, and a reflected light control unit 21 that adds transmission data to the reflected light of the power supply light transmitted from the power supply device 10 for power supply light and transmits the data to the power supply source.

[0041] This allows the communication device 20 to transmit data without using an optical transceiver, which consumes a lot of power, thereby reducing the power consumption of a communication device that is powered by power obtained through optical power feeding.

[0042] Furthermore, the communication device 20 uses at least intensity modulation or phase modulation as a means for adding transmission data to the reflected light of the power supply light. This allows the transmission data to be added to the reflected light in a simple manner. As a result, data transmission to the power supply device 10 becomes possible.

[0043] Second Embodiment A typical communication device is equipped with an optical transceiver as described in FIG. 11 . However, in a conventional configuration, if the optical transceiver fails, communication from the communication device to the central office becomes impossible. Furthermore, as described above, the information transmission process using the optical transceiver consumes a large amount of power. Therefore, in the second embodiment, a configuration is described that combines the configuration described in the first embodiment with an optical transceiver. Specifically, under normal circumstances, communication from the communication device to the power supply device is performed using the optical transceiver as in the conventional case, and when certain conditions are met, communication is performed using reflected light as in the first embodiment.

[0044] 9 is a diagram showing an example of the configuration of an optical communication system 100a according to the second embodiment. The optical communication system 100a includes a power supply device 10 and a communication device 20a. The power supply device 10 and the communication device 20a are connected by a plurality of optical fibers. Note that the configuration of the power supply device 10 is the same as that of the first embodiment, and therefore a description thereof will be omitted.

[0045] The communication device 20a is a device driven by power obtained from the power supply light transmitted from the power supply device 10. The communication device 20a switches between two transmission methods based on specific conditions. For example, the communication device 20a normally transmits data using an optical transceiver as a first transmission method, and when specific conditions are met, transmits data using a second transmission method in which data is added to reflected light (the method described in the first embodiment). The specific conditions include when communication using the optical transceiver 25a may be impossible. Examples of cases where communication using the optical transceiver 25a may include when an abnormality such as a failure occurs in the optical transceiver, or when the amount of power stored in the power storage unit 23 is less than a threshold.

[0046] Next, the specific configuration of the communication device 20a will be described. The communication device 20a includes a reflected light control unit 21, a photoelectric conversion unit 22, a power storage unit 23, a signal processing unit 24a, and an optical transceiver 25a (optical communication unit). The communication device 20a differs in configuration from the communication device 20 in that it includes a signal processing unit 24a instead of the signal processing unit 24, and in that it newly includes an optical transceiver 25a. The other configuration of the communication device 20a is the same as that of the communication device 20. Therefore, the differences from the communication device 20 will be mainly described.

[0047] The signal processing unit 24a outputs transmission data to the optical transceiver 25a until a specific condition is satisfied. When the specific condition is satisfied, the signal processing unit 24a outputs the transmission data to the reflected light control unit 21. In this way, the signal processing unit 24a causes the optical transceiver 25a to transmit the transmission data until the specific condition is satisfied, and causes the reflected light control unit 21 to transmit the transmission data when the specific condition is satisfied.

[0048] When data to be transmitted is received from the signal processing unit 24 a, the reflected light control unit 21 performs the same processing as in the first embodiment. On the other hand, when data to be transmitted is not received from the signal processing unit 24 a, the reflected light control unit 21 controls the power supply light transmitted from the power supply device 10 to be output to the photoelectric conversion unit 22.

[0049] The optical transceiver 25a communicates with the power supply device 10. For example, the optical transceiver 25a converts data output from the signal processing unit 24a into an optical signal and transmits it to the power supply device 10.

[0050] 10 is a flowchart illustrating the flow of data transmission processing performed by the communication device 20a in the second embodiment. In Fig. 10, the same processes as those in Fig. 8 are denoted by the same reference numerals as in Fig. 8, and the description thereof will be omitted. It is assumed that power supply light is being transmitted from the power supply device 10 when the processing in Fig. 10 starts.

[0051] In the process of step S101, if the signal processing unit 24a determines that there is data to be transmitted (step S101-YES), the signal processing unit 24a determines whether a specific condition is satisfied (step S201). If the signal processing unit 24a determines that the specific condition is satisfied (step S201-YES), the process of step S102 is executed.

[0052] On the other hand, if the signal processing unit 24a determines that the specific condition is not satisfied (step S201—NO), the signal processing unit 24a outputs the transmission data to the optical transceiver 25a. The optical transceiver 25a controls transmission based on the transmission data output from the signal processing unit 24a (step S202). For example, the optical transceiver 25a causes an LED to emit light in response to the transmission data. This causes the optical transceiver 25a to transmit the transmission data (step S203).

[0053] In the optical communication system 100a configured as described above, communication is performed using the optical transceiver 25a when communication using the optical transceiver 25a is possible. When communication using the optical transceiver 25a becomes impossible, data transmission is performed by applying transmission data to reflected light. This allows data transmission even when the optical transceiver 25a is unavailable. This improves convenience.

[0054] (Modification 1 common to the first and second embodiments) In each of the above-described embodiments, a configuration has been described in which the position of the fusion point in the output port 212 is adjusted as a method of performing phase modulation in the reflected light control unit 21, but the method of performing phase modulation is not limited to this. For example, delay devices that impart different amounts of delay may be installed downstream of the output ports 212-1 and 212-2 (for example, between the output ports 212-1 and 212-2 and the photoelectric conversion unit 22) to impart delays to the feed light output from the output ports 212-1 and 212-2, thereby controlling the phase of the reflected light.

[0055] (Modification 2 common to the first and second embodiments) In each of the above-described embodiments, the configuration has been described in which either intensity modulation or phase modulation is performed in the reflected light control unit 21. The reflected light control unit 21 may be configured to perform both intensity modulation and phase modulation.

[0056] Although an embodiment of the present invention has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and includes designs within the scope of the gist of the present invention.

[0057] The present invention can be applied to a system that performs optical power feeding.

[0058] REFERENCE SIGNS LIST 10... power supply device, 11... light source, 12... optical transceiver, 13... circulator, 20, 20a... communication device, 21... reflected light control unit, 22... photoelectric conversion unit, 23... power storage unit, 24, 24a... signal processing unit, 25a... optical transceiver, 100, 100a... optical communication system

Claims

A communication device driven by power obtained by optical power supply, a signal processing unit that generates transmission data to be transmitted; a reflected light control unit that adds the transmission data to reflected light of power supply light transmitted from an external device for power supply light and transmits the reflected light to a power supply source; A communication device comprising: 　 The reflected light control unit modulating the reflected light to add the transmission data; The communication device according to claim 1 . 　 The reflected light control unit The transmission data is added by modulating at least the intensity or the phase of the reflected light. The communication device according to claim 2 . 　 The reflected light control unit an input port for inputting the power supply light and a plurality of output ports in which the presence or absence of fiber fusion points or the number of fiber fusion points is adjusted so that the amount of reflection of the reflected light varies; modulating the intensity of the reflected light by switching the plurality of output ports in accordance with the transmission data; The communication device according to claim 3 . 　 The reflected light control unit an input port for inputting the power supply light and a plurality of output ports adjusted so that the optical path lengths of the reflected light are different, modulating the phase of the reflected light by switching the plurality of output ports in accordance with the transmission data; The communication device according to claim 3 . 　 The reflected light control unit an input port for inputting the feeding light, a plurality of output ports for outputting the reflected light, and a delay device for giving different delays to the reflected light output from the plurality of output ports; modulating the phase of the reflected light by switching the plurality of output ports in accordance with the transmission data; The communication device according to claim 3 . 　 The reflected light control unit the transmission data is added by modulating the intensity and phase of the reflected light; The communication device according to claim 2 . 　 Further, an optical communication unit that communicates with the power supply source is provided. The signal processing unit transmitting the transmission data using the optical communication unit until a specific condition is satisfied; When the specific condition is satisfied, the reflected light control unit is used to transmit the transmission data. A communication device according to any one of claims 1 to 7. 　 a light source that outputs power supply light used for optical power supply; a receiving unit that receives transmission data added by the communication device to reflected light of the power supply light generated by reflecting the power supply light in the communication device driven by power obtained by the optical power supply; a circulator that outputs the power supply light output from the light source to an optical fiber connected to the communication device, and outputs reflected light of the power supply light transmitted by the optical fiber connected to the communication device to the receiving unit; A power supply device comprising: 　 A communication method performed by a communication device driven by power obtained by optical power supply, comprising: Generate transmission data to be transmitted, adding the transmission data to reflected light of the power supply light transmitted from the outside for power supply light and transmitting the reflected light to the power supply source; Communication method.

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