Optical power supply system and optical power supply method

Abstract

The objective is to provide a highly reliable optical power supply system. [Solution] The optical power supply system comprises a power supply device that outputs power supply light, a plurality of power receiving devices each having a photoelectric conversion element that converts the power supply light into power, a loop-shaped optical fiber cable that transmits the power supply light from the power supply device to the plurality of power receiving devices, and a coupler that distributes the power supply light to each of the plurality of power receiving devices according to a predetermined branching ratio. The system has a plurality of optical fiber cables, and the power supply device has a switch that selects the optical fiber cable from the plurality of optical fiber cables to transmit the power supply light.

Description

Technical Field

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

Background Art

[0002] As a technology for performing communication and power supply using the same cable, PoE (Power over Ethernet (registered trademark)) is known. However, PoE can only transmit over a short distance of 100 m according to the standard, and it is difficult to support long-distance transmission of about 10 km, for example. On the other hand, an optical power supply system using an optical fiber can support long-distance transmission, but since the efficiency of converting light into electricity is low, it is difficult to operate the power receiving device efficiently. Therefore, there is a need for a technology for efficiently supplying power to a plurality of power receiving devices simultaneously.

[0003] Considering efficient power supply, it is most efficient to connect one power receiving device to one power supply light. However, when the number of power receiving devices is increased, it is necessary to lay a power supply light source and a power supply optical fiber, and an increase in cost is a problem.

[0004] In response to such problems, there is disclosed an optical fiber power supply system including a power supply device including a semiconductor laser that outputs power supply light by laser oscillation using power, a plurality of power receiving devices including a photoelectric conversion element that converts the power supply light from the power supply device into power, an optical fiber cable that transmits the power supply light from the power supply device toward the plurality of power receiving devices, and a switch element that distributes the power supply light according to the ratio of the required power of each of the plurality of power receiving devices (see, for example, Patent Document 1).

[0005] There is also disclosed an optical power supply system including a power supply device that outputs power supply light, an optical branching device into which the power supply light from the power supply device is input and to which a plurality of power receiving devices that convert the power supply light into power can be connected, a detection unit that detects the number of power receiving devices connected in the optical branching device, and a power supply control unit that controls the output of the power supply light from the power supply device based on the number of power receiving devices detected by the detection unit (see, for example, Patent Document 2). [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2021-68934 [Patent Document 2] Japanese Patent Publication No. 2021-19444 [Overview of the project] [Problems that the invention aims to solve]

[0007] Conventional technology allows for the distribution of power supply light from one power supply device to multiple power receiving devices using optical switches or optical splitters. However, if a problem occurs, such as a fiber break in the optical fiber cable used for power supply that is laid over a long distance, power supply becomes impossible, and the power receiving devices become unable to operate.

[0008] This disclosure provides technology to solve the above-mentioned problems, and aims to provide a highly reliable optical power supply system that can efficiently supply power to multiple power receiving devices simultaneously and does not immediately become unable to supply power even if a malfunction occurs in the optical fiber cable used for power supply. [Means for solving the problem]

[0009] The optical power supply system of the present disclosure comprises a power supply device that outputs power supply light, a plurality of power receiving devices each having a photoelectric conversion element that converts the power supply light into power, a loop-shaped optical fiber cable that transmits the power supply light from the power supply device to the plurality of power receiving devices, and a coupler that distributes the power supply light to each of the plurality of power receiving devices according to a predetermined branching ratio, wherein the system has a plurality of optical fiber cables, and the power supply device has a switch that selects the optical fiber cable from the plurality of optical fiber cables to transmit the power supply light. [Effects of the Invention]

[0010] According to this disclosure, it is possible to provide a highly reliable optical power supply system that can efficiently supply power to multiple power receiving devices simultaneously and does not immediately become unable to supply power even if a malfunction occurs in the optical fiber cable used for power supply. [Brief explanation of the drawing]

[0011] [Figure 1] This diagram shows the overall configuration of the optical power supply system according to Embodiment 1. [Figure 2A] This diagram shows the operation of the optical power supply system according to Embodiment 1. [Figure 2B] This diagram shows the operation of the optical power supply system according to Embodiment 1. [Figure 3] This is a flowchart showing the optical power supply method according to Embodiment 1. [Figure 4] This is a diagram illustrating a specific example of the optical power supply system according to Embodiment 1. [Figure 5] This diagram shows the overall configuration of the optical power supply system according to Embodiment 2. [Figure 6] This figure shows an example of the hardware configuration of the control device for the optical power supply system according to Embodiment 2. [Figure 7] This figure shows another example of the hardware configuration of the control device for the optical power supply system according to Embodiment 2. [Modes for carrying out the invention]

[0012] The embodiments of the optical power supply system disclosed in this specification will be described below with reference to the figures. In each figure, the same reference numerals indicate the same or corresponding parts. Therefore, detailed explanations of them may be omitted to avoid redundancy.

[0013] Embodiment 1. The optical power supply system according to Embodiment 1 will be described below with reference to the diagrams. <Configuration of the optical power supply system> Figure 1 shows the overall configuration of the optical power supply system according to Embodiment 1. In the figure, the optical power supply system 1 includes a power supply device 10 and an optical power supply network 100. The power supply device 10 includes a semiconductor laser 11 which is a light source for outputting power supply light, an optical switch 12 for selecting which of the plurality of optical fiber cables 20 for power supply is used to transmit the light laser-oscillated and output from the semiconductor laser 11, and a light receiving monitor 13 for receiving and monitoring the return light of the loop-shaped optical fiber cable 20.

[0014] The optical power supply network 100 includes a plurality of power receiving devices 50 each having a photoelectric conversion element 52, a plurality of loop-shaped optical fiber cables 20_L, 20_R for transmitting the power supply light output from the power supply device 10 to the power receiving devices 50, a first coupler 30 which is an optical fiber coupler on the power supply side for connecting to the optical fiber cables 20_L, 20_R and distributing the power supply light transmitted through the optical fiber cables 20_L, 20_R according to a branching ratio, a second coupler 40 which is an optical fiber coupler on the power receiving side for combining the power supply light distributed by the first coupler 30 according to a preset branching ratio, and a power receiving optical fiber cable 70 connected to the first coupler 30 and the second coupler 40. Note that the optical fiber cables 20, 70 include optical fibers which are transmission paths.

[0015] In addition, corresponding to each of the n (n is a natural number of 2 or more) power receiving devices 50, the first coupler 30 and the second coupler 40 are provided. When corresponding to each of the power receiving devices 50_1, 50_2, 50_3, ···, 50_n, they are denoted as the first couplers 30_1, 30_2, 30_3, ···, 30_n and the second couplers 40_1, 40_2, 40_3, ···, 40_n. Also, when referring to them generically, they are denoted as the power receiving device 50, the first coupler 30, and the second coupler 40.

[0016] In addition, the optical fiber cable 70 connected to the first coupler 30 and the second coupler 40 is composed of the same number as the loop-shaped optical fiber cable 20. In the figure, two optical fiber cables 70_L1, 70_R1, 70_L2, 70_R2, 70_L3, 70_R3, ···, 70_Ln, 70_Rn are provided for each power receiving device 50. When referring to them generically, they are denoted as the optical fiber cable 70.

[0017] In the figure, there are two loop-shaped optical fiber cables 20_L and 20_R. They are composed of the first optical fiber cable 20_L that rotates counterclockwise, that is, in the counterclockwise direction, and the second optical fiber cable 20_R that rotates clockwise, that is, in the clockwise direction. Note that the optical fiber cable 20 is not limited to two, but it is desirable that those that transmit the power supply light in different directions such as counterclockwise and clockwise are included. Here, the different directions mean that the order in which the power supply light output from the power supply device is transmitted to a plurality of power receiving devices is different from others. Note that the second optical fiber cable 20_R not selected by the optical switch 12 is shown by a dotted line.

[0018] In the figure, the optical switch 12 of the power supply device 10 connects the output of the semiconductor laser 11 and the optical connector 21_Ls on the input side of the optical fiber cable 20_L, and connects the optical connector 21_Lr on the output side of the optical fiber cable 20_L and the light receiving monitor 13. The power supply light λL output from the semiconductor laser 11 is transmitted through the optical fiber cable 20_L and is distributed according to the branching ratio of each first coupler 30. That is, the power supply light λL output from the semiconductor laser 11 is transmitted through the optical fiber cable 20_L, and the power supply light λL having an output ratio excluding the power supply light λL1 distributed at the branching ratio of the first coupler 30_1 is distributed according to the branching ratio at the first coupler 30_2. Further, the power supply light λL having an output ratio excluding the power supply light λL2 is sequentially distributed so as to be distributed according to the branching ratio at the first coupler 30_3, and the remaining output power supply light as the return light λL0 is input from the optical connector 21_Lr on the output side of the first optical fiber cable 20_L to the light receiving monitor 13.

[0019] Furthermore, the power supply light λL1 distributed by the first coupler 30_1 is transmitted through the power receiving optical fiber cable 70_L1, combined according to the pre-set branching ratio of the second power receiving coupler 40_1, and the combined power supply light λ1 is converted into power by the photoelectric conversion element 52_1 of the power receiving device 50_1. The same applies to the power supply light λL2 distributed by the first coupler 30_2. The branching ratios of the first coupler 30 and the second coupler 40 will be described later.

[0020] Figure 1 shows an example where the output of the semiconductor laser 11 is connected to the optical fiber cable 20_L by the optical switch 12 of the power supply device 10. However, the same applies when connected to the optical fiber cable 20_R, which transmits the power supply light in a clockwise direction; therefore, the explanation is omitted.

[0021] <Operation of Optical Power Supply System 1> Next, the operation of the optical power supply system 1 will be explained using diagrams. Figures 2A and 2B show the operation of the optical power supply system 1 according to Embodiment 1, and Figure 3 is a flowchart showing the operation of the optical power supply system 1, i.e., the optical power supply method. The operation of the optical power supply system 1 will be explained according to the flowchart in Figure 3, with reference to Figures 2A and 2B. In step S1, as shown in Figure 2A, the power supply light λL output from the power supply device 10 is transmitted through the first optical fiber cable 20_L selected by the optical switch 12.

[0022] In step S2, the light receiving monitor 13 monitors the first optical fiber cable 20_L for abnormalities based on the reflected light λL0. If there are no abnormalities, the process proceeds to step S3 (No in step S2). As shown in Figure 2A, if an abnormality occurs in the first optical fiber cable 20_L, such as a break in the fiber at point P, the intensity of the reflected light λL0 decreases or becomes zero, so the light receiving monitor 13 can detect the abnormality in the first optical fiber cable 20_L. If an abnormality is detected, proceed to step S6 (Yes in step S2).

[0023] If there is no abnormality in step S2, in step S3, the power is distributed according to the branching ratio of each first coupler 30. The power supply light λL transmitted by the optical fiber cable 20_L is distributed from the first coupler 30_1 according to the branching ratio, and the remaining output is distributed sequentially to the next first coupler 30_2.

[0024] In step S4, the power supply light λL1, λL2, λL3, ..., λLn distributed by each first coupler 30 are combined by each second coupler 40 according to the branching ratio, and power supply light λ1, λ2, λ3, ..., ...λn are output.

[0025] In step S5, the power supply light λ1, λ2, λ3, ..., λn output from each second coupler 40 is converted by the photoelectric conversion element 52 of each power receiving device 50, and each power receiving device 50 receives power.

[0026] If an abnormality is detected in step S2, in step S6, the optical switch 12 is switched to select the second optical fiber cable 20_R for power supply, as shown in Figure 2B. Specifically, the output of the semiconductor laser 11 is switched from optical connector 21_Ls to optical connector 21_Rs, and the connection to the light receiving monitor 13 is switched from optical connector 21_Lr to optical connector 21_Rr. As a result of this switching, the power supply light λR output from the power supply device 10 is transmitted through the second optical fiber cable 20_R.

[0027] In step S6, when the optical fiber cable is switched to a healthy one, in step S3, the power supply optical fiber λR transmitted through the second optical fiber cable 20_R is distributed according to the branching ratio of each first coupler 30. The power supply optical fiber λR transmitted through the optical fiber cable 20_R is distributed from the first coupler 30_n according to the branching ratio, and the remaining output is distributed sequentially to the next first coupler 30_n-1.

[0028] In step S4, the power supply light λR1, λR2, λR3, ..., λRn distributed by each first coupler 30 are combined by each second coupler 40 according to the branching ratio, and power supply light λ1, λ2, λ3, ..., λn are output. In step S5, the power supply light λ1, λ2, λ3, ..., λn output from each second coupler 40 is converted by the photoelectric conversion element 52 of each power receiving device 50, and each power receiving device 50 receives power.

[0029] Steps S1 through S6 are executed repeatedly.

[0030] In this way, by using multiple power supply optical fiber cables 20, detecting an abnormality in one optical fiber cable 20, and switching to another healthy power supply optical fiber cable 20, it becomes possible to continue supplying power from the power supply device 10. Furthermore, since the power supply optical fiber cable 20 is loop-shaped, abnormalities in the optical fiber cable 20 during use can be easily detected by monitoring the reflected light on the power supply device 10 side (light receiving monitor 13).

[0031] <Branching ratio of the first coupler 30> Next, we will explain how to set the branching ratio for the first coupler 30, which is the optical fiber coupler on the power supply side. The power supply light output from the semiconductor laser 11 of the power supply device 10 is transmitted via the optical switch 12 through the power supply optical fiber cable 20 and passes through the first couplers 30_1, 30_2, 30_3, ..., 30_n. As the power supply light passes further down the line, the output of the power supply light reaching it decreases, resulting in lower power supply. Consequently, the power supply may not reach the required power, and may not be able to operate, especially in the power receiving device 50 further down the line. Therefore, by making it possible to arbitrarily select the branch ratio of the first couplers 30_1, 30_2, 30_3, ..., 30_n, such as 1:x1, 1:x2, 1:x3, ..., 1:xn, the power supply can be distributed so that all power receiving devices 50 can operate correctly.

[0032] For example, as shown in Figure 1, when the power supply light λL is transmitted through a counterclockwise optical fiber cable 20_L, the first coupler 30_1 initially distributes the power supply light, assuming a branching ratio of 1:1. In this case, 50% of the output of the power supply light λL output from the semiconductor laser 11 is distributed by the first coupler 30_1, and the remaining 50% of the power supply light passes through the first couplers 30_2, 30_3, ..., 30_n. Consequently, the power receiving devices 50_2, 50_3, ..., 50_n can only receive less than 50% of the total power supply. If there is a device with high power consumption among the power receiving devices 50_2, 50_3, ..., 50_n, there is a possibility that it will not operate correctly.

[0033] For example, if the branching ratio of the first coupler 30_1, which initially distributes the power supply light, is changed from 1:1 to 1:4, then 80% of the output will be transmitted to the subsequent first couplers 30_2, 30_3, ..., 30_n, and the power receiving devices 50_2, 50_3, ..., 50_n will be able to transmit 80% of the total power supply. Therefore, it is desirable to set the branching ratio of each first coupler 30_1, 30_2, 30_3, ..., 30_n based on the required power of each power receiving device 50_1, 50_2, 50_3, ..., 50_n. This makes it possible to efficiently and simultaneously supply power to all power receiving devices 50 without any shortage.

[0034] Furthermore, if an abnormality is detected while transmitting the power supply light λL through the counterclockwise optical fiber cable 20_L, the system switches to the clockwise optical fiber cable 20_R, as shown in Figure 2B. In this case, the first coupler 30_n will be the first to distribute the power supply light. Even after the switch, in order to efficiently and simultaneously supply power to all power receiving devices 50 without any shortage, it is necessary to set the branching ratio of each first coupler 30 for each transmission direction of the loop-shaped optical fiber cable based on the required power of each power receiving device 50.

[0035] <Branching ratio of the second coupler 40> Next, we will explain how to set the branching ratio for the second coupler 40, which is the optical fiber coupler on the power receiving side. The power supply light output from the semiconductor laser 11 of the power supply device 10 is transmitted through one optical fiber cable 20 selected by the optical switch 12, and the power supply light distributed via the first coupler 30 is combined by the second coupler 40. For the sake of simplicity, we will now describe the case where two optical fiber cables 20_L and 20_R are used as power supply optical fiber cables.

[0036] For example, the power supply light distributed by the first coupler 30_1 consists of power supply light λL1 transmitted and distributed through the optical fiber cable 20_L and power supply light λR1 transmitted and distributed through the optical fiber cable 20_R, and the second coupler 40_1 has a branching ratio that combines power supply light λL1 and power supply light λR1.

[0037] Here, let's assume that the outputs of the power supply light λL1 and power supply light λR1 reaching the second coupler 40_1 are converted to power supply power of 90mW and 30mW, respectively. If the branch ratio of the second coupler 40_1 is 1:1, then the output of power supply light λL1 after passing through the second coupler 40_1 will be 45mW, and the output of power supply light λR1 after passing through the second coupler 40_1 will be 15mW. If the power required to operate the device of the power receiving device 50_1 is 15mW, there is no problem, but if the required power is 20mW, the device of the power receiving device 50_1 may not operate.

[0038] For example, if the branching ratio of the second coupler 40_1 is changed from 1:1 to 1:2, the output of the power supply light λL1 passing through the second coupler 40_1 will be 30mW, and the output of the power supply light λR1 passing through the second coupler 40_1 will be 20mW. As a result, even if an abnormality occurs in the optical fiber cable 20_L and it is switched to the optical fiber cable 20_R, it will be possible to receive the 20mW of power necessary to drive the device of the power receiving device 50_1 before and after the switch.

[0039] Therefore, it is desirable to set not only the branching ratio of each first coupler 30_1, 30_2, 30_3, ..., 30_n, but also the branching ratio of each second coupler 40_1, 40_2, 40_3, ..., 40_n, based on the required power of each power receiving device 50_1, 50_2, 50_3, ..., 50_n. This makes it possible to supply power to all power receiving devices 50 efficiently and simultaneously without any shortages.

[0040] While providing multiple power supply fiber optic cables 20 allows for switching to a healthy cable 20 when an anomaly is detected, increasing the number of cables increases redundancy. However, a larger number of cables may also reduce the power received due to the branching ratio at the second coupler. Therefore, it is better to limit the number of cables to an appropriate number. Furthermore, to enhance redundancy, multiple power supply optical fiber cables 20 should be laid at predetermined distances from each other. This is because an event that detects an abnormality in one power supply optical fiber cable 20 may affect other nearby power supply optical fiber cables 20. Therefore, a highly reliable redundant system can be achieved by laying them at predetermined distances from each other and including at least one optical fiber cable 20 supplying power in the opposite direction.

[0041] Therefore, it is desirable that the semiconductor laser 11 of the power supply device 10 has an output that is sufficiently larger than the sum of the power required by each power receiving device 50, and that the number of power supply optical fiber cables 20, the branching ratio of the first coupler 30, and the branching ratio of the second coupler 40 be set so that the required power can be supplied to each power receiving device 50. Furthermore, the output of the semiconductor laser 11 should ideally be set to a maximum of approximately 500mW, taking into consideration its strength to prevent damage to the optical fiber cable.

[0042] <Example 1> Next, we will explain specific examples of setting the branch ratios for the first coupler 30 and the second coupler 40. Figure 4 shows an example of setting the branch ratio of the first coupler 30 and the branch ratio of the second coupler 40 in the optical power supply system 1 according to Embodiment 1. Here, the optical power supply system 1 is the same as that shown in Figure 1, and the output of the semiconductor laser 11 of the power supply device 10 is 250mW. Power is supplied to three power receiving devices 50_1, 50_2, and 50_3, with the required power of the three power receiving devices 50_1, 50_2, and 50_3 being 20mW, 40mW, and 30mW, respectively. Two power supply optical fiber cables 20 are used, and the branch ratios of each first coupler 30 for the power supply light λL transmitted through the counterclockwise optical fiber cable 20_L and the power supply light λR transmitted through the clockwise optical fiber cable 20_R are as shown in Figure 4. The power shown is the power converted from the power supply light distributed by the first coupler 30. Furthermore, the branching ratios of each second coupler 40 are as shown in Figure 4.

[0043] While the power supply light λL is being transmitted through the counterclockwise optical fiber cable 20_L, the power of the power supply light λL1 distributed at the first coupler 30_1 is 50mW, and the power of the power supply light λL2 distributed at the first coupler 30_2 according to the branching ratio from the 200mW (250mW-50mW) power supply light is 80mW. At the first coupler 30_3, the power of the power supply light λL3 distributed according to the branching ratio from the 120mW (200mW-80mW) power supply light is 100mW.

[0044] At this time, the power of the power supply light λ1 output via the second coupler 40_1 is 25mW according to the branching ratio, the power of the power supply light λ2 output via the second coupler 40_2 is 53.3mW according to the branching ratio, and the power of the power supply light λ1 output via the second coupler 40_1 is 33.3mW according to the branching ratio. In all cases, the required power of the power receiving devices 50_1, 50_2, and 50_3 is 20mW, 40mW, and 30mW, respectively.

[0045] Similarly, while the power supply light λL is being transmitted through the clockwise optical fiber cable 20_R, the power of the power supply light λR1 distributed at the first coupler 30_3 is 50mW, and the power of the power supply light λR2 distributed at the first coupler 30_2 according to the branching ratio from the 200mW (250mW-50mW) power supply light is 150mW. At the first coupler 30_1, the power of the power supply light λR3 distributed according to the branching ratio from the 50mW (200mW-150mW) power supply light is 40mW.

[0046] At this time, the power of the power supply light λ1 output via the second coupler 40_1 is 20mW according to the branching ratio, the power of the power supply light λ2 output via the second coupler 40_2 is 50mW according to the branching ratio, and the power of the power supply light λ1 output via the second coupler 40_1 is 33.3mW according to the branching ratio. In all cases, the required power of the power receiving devices 50_1, 50_2, and 50_3 is 20mW, 40mW, and 30mW, respectively.

[0047] As described above, the optical power supply system according to this embodiment 1 comprises a power supply device that outputs power supply light, a plurality of power receiving devices each having a photoelectric conversion element that converts power supply light into electricity, a loop-shaped optical fiber cable that transmits power supply light from the power supply device to the plurality of power receiving devices, and a coupler that distributes power supply light to each of the plurality of power receiving devices according to a preset ratio. The system has a plurality of optical fiber cables, and the power supply device has a switch that selects the optical fiber cable from the plurality of optical fiber cables to which the power supply light is transmitted. With this configuration, if an abnormality such as a fiber break occurs in the optical fiber cable that is transmitting power supply light, it is possible to continue supplying power from the power supply device by selecting another optical fiber cable. Therefore, it is possible to provide a highly reliable optical power supply system.

[0048] Furthermore, the power supply device has a light receiving monitor that receives the return light from the optical fiber cable transmitting the power supply light. If this light receiving monitor detects an abnormality in the optical fiber cable transmitting the power supply light, a switch is activated to switch to another optical fiber cable. By monitoring the return light from the loop-shaped optical fiber cable with the power supply device (light receiving monitor), it becomes possible to easily detect abnormalities in the power receiving optical fiber cable in use.

[0049] Furthermore, the coupler that distributes the power supply light to each of the multiple power receiving devices according to a preset ratio includes a first coupler connected to the optical fiber cable and a second coupler connected to the power receiving device, each corresponding to a power receiving device. The branching ratio of the first coupler is set for each of the multiple optical fiber cables, and the power supply light transmitted through the optical fiber cable is distributed according to the branching ratio of the first coupler. The power supply light distributed from the multiple optical fiber cables is combined according to the branching ratio of the second coupler. This makes it possible to set the branching ratio of the first coupler and the branching ratio of the second coupler so that each power receiving device can be supplied with the necessary power. This makes it possible to provide a highly reliable optical power supply system that can supply the necessary power to the power receiving devices even when switching optical fiber cables.

[0050] Embodiment 2. The optical power supply system according to Embodiment 2 will be described below with reference to the diagrams. Figure 5 shows the overall configuration of the optical power supply system according to Embodiment 2. It differs from the configuration of Embodiment 1 in that it includes a control device 15 that receives a signal from the light receiving monitor 13 indicating an abnormality in the optical fiber cable 20 and controls the switching of the optical fiber cable 20 at the optical switch 12. The other configurations are the same as in Embodiment 1, so their explanation will be omitted.

[0051] In this way, by using the control device 15 and controlling the switching of the optical fiber cable 20 based on the abnormality detection signal from the light receiving monitor 13, the work of the workers is made more efficient, and 24-hour monitoring and switching are possible. Furthermore, the control device 15 and the light receiving monitor 13 may be combined into a monitoring device to monitor and control multiple power supply devices 10.

[0052] Figures 6 and 7 show an example of the hardware configuration of the control device 15 in the above-described embodiment 2, which includes an arithmetic processing circuit 110 and a storage device 120. Although not shown in the figures, the storage device includes auxiliary storage devices such as a ROM (Read Only Memory) that stores programs for executing the functions of each functional unit, and a RAM (Random Access Memory) that stores the execution results data of each functional unit, which are the calculation results of the programs. It may also include auxiliary storage devices such as a hard disk. The arithmetic processing circuit 110 executes the program input from the storage device 120. In this case, the program is input to the arithmetic processing circuit 110 from the auxiliary storage device via a volatile storage device. The arithmetic processing circuit 110 may also output data such as calculation results to the volatile storage device of the storage device 120, or it may store the data in the auxiliary storage device via the volatile storage device.

[0053] Furthermore, the control device 15 may also include an input / output circuit 130 and a communication circuit 140. The input / output circuit 130 and the communication circuit 140 are used for sending and receiving data with multiple power supply devices 10. In addition, during periodic inspections, etc., workers can input the switching of optical fiber cables from a work terminal (not shown).

[0054] The communication circuit 140 can use a communication module compliant with, for example, LTE (Long Term Evolution), 4G (4th Generation), or 5G (5th Generation). Furthermore, if the control device 15 and the light receiving monitor 13 are located close together, wireless or wired LAN (Local Area Network), Wi-Fi (registered trademark), and Bluetooth (registered trademark) can be used.

[0055] The arithmetic processing circuit 110 may be a processor such as a CPU (Central Processing Unit) or a DSP (Digital Signal Processor). Alternatively, dedicated hardware may be used for the arithmetic processing circuit 110. If the arithmetic processing circuit 110 is dedicated hardware, it may be, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination thereof.

[0056] Although examples with multiple optical fiber cables were described in Embodiments 1 and 2, only one optical fiber cable may be used. Even with a single optical fiber, the basic configuration of the power supply system 1 is the same as in Figure 1. In Figure 1, the optical switch 12 selects the optical connector 21 and determines the output direction. For example, the power supply optical fiber cable 20 transmits the power supply light λL output from the power supply device 10, and the light receiving monitor 13 monitors for any abnormalities in the optical fiber cable 20 using the return light λL0. If an abnormality is detected, the optical switch 12 switches the optical connector 21 to transmit the power supply light λR. Thereafter, the optical switch 12 switches the output from the power supply device between the power supply light λL and the power supply light λR, thereby continuing to supply power to multiple power receiving devices 50. In Figure 1, if a break occurs in the optical fiber cable between the first coupler 30_2 and the first coupler 30_3, power is supplied to the receiving devices 50_1 and 50_2 by the power supply light λL, and power can be supplied from the receiving device 50_3 to the receiving device 50_2 by the power supply light λR. If there is only one fiber optic cable, a break in the cable will prevent further detection of abnormalities in the fiber optic cable through reflected light during subsequent power supply, but the cost of laying fiber optic cables can be reduced.

[0057] The various aspects of this disclosure are summarized below as an appendix.

[0058] (Note 1) A power supply device that outputs power supply light, A plurality of power receiving devices, each having a photoelectric conversion element that converts the aforementioned power supply light into electrical power, A loop-shaped optical fiber cable that transmits the power supply light from the power supply device to a plurality of the power receiving devices, The system includes a coupler that distributes the aforementioned power supply light to each of the multiple power receiving devices according to a predetermined branching ratio, Having multiple optical fiber cables, The power supply device is an optical power supply system having a switch that selects the optical fiber cable from a plurality of optical fiber cables to transmit the power supply light. (Note 2) The power supply device is The system includes a light receiving monitor that receives the return light from the optical fiber cable that transmits the power supply light, The optical power supply system as described in Appendix 1, wherein if the light receiving monitor detects an abnormality in the optical fiber cable transmitting the power supply light, the switch switches to another optical fiber cable. (Note 3) The coupler includes a first coupler connected to the optical fiber cable and corresponding to each of the power receiving devices, and a second coupler connected to the power receiving device. The power supply light transmitted through the optical fiber cable is distributed according to the branching ratio of the first coupler. The optical power supply system according to Appendix 1 or 2, wherein the power supply light distributed from a plurality of optical fiber cables is combined according to the branching ratio of the second coupler. (Note 4) The branching ratio of the first coupler is set for each of the multiple optical fiber cables in the optical power supply system as described in Appendix 3. (Note 5) The optical power supply system according to any one of the appendices 1 to 4, wherein the power supply device comprises a semiconductor laser, and the light output from the semiconductor laser is transmitted as the power supply light through the optical fiber cable selected by the switch. (Note 6) The optical power supply system according to any one of the appendices 1 to 5, wherein at least one of the multiple optical fiber cables transmits the power supply light output from the power supply device to the multiple power receiving devices in a different order from the others. (Note 7) An optical power supply method comprising transmitting the power supply light from a power supply device that outputs power supply light to a plurality of power receiving devices having photoelectric conversion elements that convert the power supply light into electricity, using optical fiber cables, A step of selecting one optical fiber cable from among the multiple optical fiber cables and outputting the power supply light, The steps include: distributing the power supply light transmitted through the optical fiber cable according to the branching ratio of a first coupler connected to the optical fiber cable; The steps include combining the power supply light distributed by the first coupler according to the branching ratio of the second coupler connected to the power receiving device and transmitting it to the power receiving device, The system includes the step of converting the power supply light, which has been combined by the second coupler, into power by photoelectric conversion and receiving the power, An optical power supply method comprising the step of switching to another optical fiber cable and outputting the power supply light from the power supply device when an abnormality is detected in the selected optical fiber cable. (Note 8) The optical power supply method described in Appendix 7, wherein the multiple optical fiber cables are in a loop shape, and abnormalities in the optical fiber cables are detected by monitoring the reflected light from the optical fiber cables.

[0059] While this disclosure describes various exemplary embodiments and examples, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but are applicable individually or in various combinations to the embodiments. Accordingly, countless variations not illustrated are conceivable within the scope of the art disclosed in this specification. These include, for example, modifying, adding or omitting at least one component, or even extracting at least one component and combining it with components of other embodiments. [Explanation of Symbols]

[0060] 1: Optical power supply system, 10: Power supply device, 11: Semiconductor laser, 12: Optical switch, 13: Light receiving monitor, 15: Control device, 20, 20_L, 20_R: Optical fiber cable, 21, 21_Ls, 21_Lr, 21_Rs, 21_Rr: Optical connector, 30, 30_1, 30_2, 30_3, 30_n: First coupler, 40, 40_1, 40_2, 40_3, 40_n: Second coupler, 50, 50_1, 50_2, 50_3, 50_n: Power receiving device, 52, 52_1, 52_2, 52_3, 52_n: Photoelectric conversion element 70, 70_L1, 70_R1, 70_L2, 70_R2, 70_L3, 70_R3, 70_Ln, 70_Rn: Optical fiber cable, 100: Optical power supply network, 110: Processing circuit, 120: Memory device, 130: Input / output circuit, 140: Communication circuit.

Claims

1. A power supply device that outputs power supply light, A plurality of power receiving devices, each having a photoelectric conversion element that converts the aforementioned power supply light into electrical power, A loop-shaped optical fiber cable that transmits the power supply light from the power supply device to a plurality of the power receiving devices, The system includes a coupler that distributes the aforementioned power supply light to each of the multiple power receiving devices according to a predetermined branching ratio, Having multiple optical fiber cables, The power supply device is an optical power supply system having a switch that selects the optical fiber cable from a plurality of optical fiber cables to transmit the power supply light.

2. The power supply device is The system includes a light receiving monitor that receives the return light from the optical fiber cable that transmits the power supply light, The optical power supply system according to claim 1, wherein if the light receiving monitor detects an abnormality in the optical fiber cable transmitting the power supply light, the switch switches to another optical fiber cable.

3. The coupler includes a first coupler connected to the optical fiber cable and corresponding to each of the power receiving devices, and a second coupler connected to the power receiving device. The power supply light transmitted through the optical fiber cable is distributed according to the branching ratio of the first coupler. The optical power supply system according to claim 1 or 2, wherein the power supply light distributed from a plurality of optical fiber cables is combined according to the branching ratio of the second coupler.

4. The optical power supply system according to claim 3, wherein the branching ratio of the first coupler is set for each of the multiple optical fiber cables.

5. The optical power supply system according to claim 1 or 2, wherein the power supply device comprises a semiconductor laser, and the light output from the semiconductor laser is transmitted as power supply light through the optical fiber cable selected by the switch.

6. The optical power supply system according to claim 1 or 2, wherein at least one of the multiple optical fiber cables transmits the power supply light output from the power supply device to the multiple power receiving devices in a different order from the others.

7. An optical power supply method comprising transmitting the power supply light from a power supply device that outputs power supply light to a plurality of power receiving devices having photoelectric conversion elements that convert the power supply light into electricity, using optical fiber cables, A step of selecting one optical fiber cable from among the multiple optical fiber cables and outputting the power supply light, The steps include: distributing the power supply light transmitted through the optical fiber cable according to the branching ratio of the first coupler connected to the optical fiber cable; The steps include combining the power supply light distributed by the first coupler according to the branching ratio of the second coupler connected to the power receiving device and transmitting it to the power receiving device, The system includes the step of converting the power supply light combined by the second coupler into power by photoelectric conversion and receiving the power, An optical power supply method comprising the step of switching to another optical fiber cable and outputting the power supply light from the power supply device when an abnormality is detected in the selected optical fiber cable.

8. The optical power supply method according to claim 7, wherein the plurality of optical fiber cables are in a loop shape, and abnormalities in the optical fiber cables are detected by monitoring the reflected light from the optical fiber cables.

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