Optical modulation device and optical power supply data transmission system

Abstract

To reduce energy consumption in a system for supplying light energy from one of two devices connected by an optical fiber to the other device and operating the other device by the light energy.SOLUTION: The optical modulation device 40 includes an optical splitter 62 that splits input light into two light beams, a power supply unit 30 that converts one of the two light beams obtained by the optical splitter 62 into power, and a modulation unit 88 that modulates light based on the other of the two light beams obtained by the optical splitter 62 with data to be transmitted to generate modulated light. The power supply unit 30 supplies power to the modulation unit 88. The optical modulation device 40 also includes an optical amplifier that pumps light having a predetermined wavelength based on the other of the two light beams obtained by the optical splitter 62. The modulation unit 88 modulates the light excited by the optical amplifier.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an optical modulation device and an optically powered data transmission system, and more particularly to a technique for supplying power from a power source to an optical modulation device. [Background technology]

[0002] Research and development is being conducted on a system that collects detected values ​​via optical fibers from various sensors, such as temperature sensors, humidity sensors, image sensors, and acceleration sensors. In this system, detected values ​​are transmitted from a device equipped with the sensor to a data receiving device via optical fibers. Even if the sensor is installed in a remote location where it is difficult for a user to immediately go, or in a location where it is difficult for people to enter or exit, such as a location where there is a risk of radiation exposure, a location where high voltage is used, or a location where temperatures are maintained higher or lower than normal, the user can obtain detected values ​​from the sensor.

[0003] The following Patent Document 1 describes a system in which energy is supplied from a sensor control device to a sensor device via an optical fiber, and information detected by the sensor device is transmitted from the sensor device to the sensor control device via the optical fiber. Patent Documents 2 and 3 describe an optical power supply system in which energy is supplied by light from one of two devices connected by an optical fiber to the other. Information is transmitted by light from the other of two devices connected by an optical fiber to the first device. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-127554 [Patent Document 2] Japanese Patent Application Publication No. 2023-144633 [Patent Document 3] Japanese Patent Publication No. 2023-153145 Summary of the Invention [Problem to be solved by the invention]

[0005] In conventional technology, two devices connected by an optical fiber are connected, and energy is supplied by light from one (first device) to the other (second device). The second device converts the optical energy supplied from the first device into electrical energy and generates light for information transmission based on the electrical energy. In such a configuration, the conversion of optical energy to electrical energy and the electrical energy being converted back into optical energy can result in significant energy loss.

[0006] The present invention aims to reduce energy consumption in a system in which optical energy is supplied from one of two devices connected by an optical fiber to the other, and the other device operates using optical energy. [Means for solving the problem]

[0007] The optical modulation device of the present invention comprises an optical branching unit that branches input light into two, a power supply unit that converts one of the two lights obtained by the optical branching unit into electric power, and a modulation unit that modulates the light based on the other of the two lights obtained by the optical branching unit with data to be transmitted to generate modulated light, and is characterized in that the power supply unit supplies power to the modulation unit.

[0008] In one embodiment, an optical amplifier is provided that excites light of a predetermined wavelength based on the other of the two lights obtained by the optical branching device, and the modulation unit modulates the light excited by the optical amplifier.

[0009] In one embodiment, the optical amplifier includes a resonating optical fiber and a resonating loop extending from the downstream end of the resonating optical fiber back to the upstream end.

[0010] In one embodiment, the optical amplifier comprises a resonance optical fiber, an upstream transmission mirror provided at the upstream end of the resonance optical fiber, and a downstream transmission mirror provided at the downstream end of the resonance optical fiber.

[0011] In one embodiment, the resonating optical fiber is an erbium-doped optical fiber.

[0012] In one embodiment, the power supply unit includes an opto-electrical converter that converts one of the two lights obtained by the optical branching unit into electricity, and a battery that is charged by the electricity output from the opto-electrical converter, and outputs electricity from at least one of the opto-electrical converter and the battery.

[0013] In one embodiment, a sensor is connected and a sensor control unit is provided that generates sensor data including the detection value of the sensor, and the modulation unit modulates light based on the other of the two lights obtained by the optical branching unit using the sensor data.

[0014] The optical power supply data transmission system of the present invention is characterized by comprising: the optical modulation device; an input terminal provided in the optical modulation device and into which the input light is input; an output terminal provided in the optical modulation device and from which the modulated light is output; an optical transmitter unit that outputs light for supplying energy to an upstream end of a power supply optical fiber whose downstream end is connected to the input terminal; and a data demodulator that acquires the modulated light from the downstream end of a data transmission optical fiber whose upstream end is connected to the output terminal, and demodulates the modulated light to extract the data. [Effects of the Invention]

[0015] According to the present invention, it is possible to reduce energy loss in a system in which optical energy is supplied from one of two devices connected by an optical fiber to the other, and the other device operates using the optical energy. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a diagram illustrating a configuration of an optical power supply data transmission system. [Figure 2] FIG. 1 is a diagram illustrating a configuration example of an optical power supply data receiving device. [Figure 3]FIG. 1 is a diagram illustrating an example of the configuration of an optical modulation device. [Figure 4] FIG. 1 is a diagram illustrating an example of the configuration of an optical modulation device. DETAILED DESCRIPTION OF THE INVENTION

[0017] An embodiment of the present invention will be described with reference to the drawings. Identical components shown in multiple drawings are designated by the same reference numerals to simplify the description. FIG. 1 shows the configuration of an optical power supply data transmission system 100 according to an embodiment of the present invention. The optical power supply data transmission system 100 includes an optical power supply data receiving device 10, an optical modulation device 40, and a sensor 42.

[0018] The optical power supply data receiving device 10 and the optical modulator 40 are connected by a power supply optical fiber 50 and a data transmission optical fiber 52. In one embodiment, the power supply optical fiber 50 and the data transmission optical fiber 52 have lengths of 1 km to 5 km, but the lengths of these optical fibers may be less than 1 km or more than 5 km depending on the application. The optical power supply data receiving device 10 outputs energy light for supplying energy to the power supply optical fiber 50. The power supply optical fiber 50 transmits the energy light output from the optical power supply data receiving device 10 to the optical modulator 40.

[0019] The optical modulator 40 converts energy based on the energy light transmitted through the power supply optical fiber 50 into electrical power. The optical modulator 40 uses the electrical power converted from the energy light as power supply power. The optical modulator 40 also uses a portion of the energy light transmitted through the power supply optical fiber 50 as light for transmitting data to the optical power supply data receiving device 10. The sensor 42 outputs a detection value based on a physical quantity detected by the sensor 42 to the optical modulator 40. The optical modulator 40 modulates the light for data transmission using sensor data based on the detection value output by the sensor 42 to generate modulated light. That is, the optical modulator 40 modulates the light for data transmission using sensor data, which is data to be transmitted, to generate modulated light.

[0020] The optical modulator 40 outputs modulated light to a data transmission optical fiber 52. The data transmission optical fiber 52 transmits the modulated light output from the optical modulator 40 to the optical power supply data receiving device 10. The optical power supply data receiving device 10 demodulates the modulated light transmitted by the data transmission optical fiber 52 and extracts sensor data from the modulated light.

[0021] 2 shows an example configuration of an optically powered data receiving device 10. The optically powered data receiving device 10 includes a laser diode control unit 12, a laser diode 14, a transmitting terminal 18, a receiving terminal 20, an opto-electrical converter 22, a data demodulation unit 24, a control unit 26, and a network interface 28. However, in FIG. 2, the laser diode control unit 12 is referred to as the "LD control unit," and the network interface 28 is referred to as the "network IF." The laser diode control unit 12, the data demodulation unit 24, the control unit 26, and the network interface 28 may each include one or more processors that execute programs to realize some or all of their functions.

[0022] FIG. 3 shows an example configuration of an optical modulation device 40. The optical modulation device 40 includes an input terminal 60, an optical splitter 62, a power supply unit 30, a modulated light generation unit 80, a sensor interface 84, a sensor control unit 86, and an output terminal 38. However, in FIG. 3, the sensor interface 84 is denoted as "sensor IF." The power supply unit 30 includes a photoelectric converter 64, a battery 66, and a power supply circuit 68, and generates power for the optical modulation device 40. The sensor interface 84 and the sensor control unit 86 may include processors that execute programs to realize some or all of their functions. Similarly, electrical circuits such as the modulation unit 88 included in the modulated light generation unit 80 may also include processors that realize some of their functions.

[0023] With reference to FIG. 2, the configuration and operation of the optical power supply data receiving device 10 for transmitting energy light will be described. The laser diode control unit 12 and the laser diode 14 constitute an optical transmitting unit that outputs energy light. The laser diode control unit 12 controls the laser diode 14 to cause the laser diode 14 to generate energy light. The laser diode 14 according to this embodiment may be a laser diode that generates light in the 1.48 μm band. Here, light in the 1.48 μm band refers to light having a predetermined wavelength band that includes light with a wavelength of 1.48 μm. Note that a light-emitting diode (LED) may be used instead of the laser diode.

[0024] The energy light emitted from the laser diode 14 is guided to the transmitting terminal 18 by the optical fiber and output to the power feeding optical fiber 50, whose upstream end is connected to the transmitting terminal 18. The power feeding optical fiber 50 transmits the energy light to the optical modulation device 40.

[0025] The configuration and operation of the optical modulation device 40 will be described with reference to Fig. 3. Energy light transmitted through the power supply optical fiber 50 is input to the optical modulation device 40 via an input terminal 60. The input terminal 60 is connected to an optical branching device 62 by an optical fiber. The energy light input to the input terminal 60 as input light is guided by the optical fiber to the optical branching device 62, where it is branched into two light beams.

[0026] The downstream side of the optical splitter 62 is connected to the photoelectric converter 64 and the modulated light generating unit 80 by two optical fibers that guide the two branched lights. One of the two lights obtained by the optical splitter 62 is guided to the photoelectric converter 64 by the optical fiber. The photoelectric converter 64 may be composed of a photodiode. The photoelectric converter 64 converts the light into electricity and outputs the electricity to the battery 66 and the power supply circuit 68.

[0027] In the power supply unit 30, power is output from at least one of the photoelectric converter 64 and the battery 66 to the power supply circuit 68. When the voltage output from the photoelectric converter 64 to the battery 66 and the power supply circuit 68 is higher than the voltage output by the battery 66, the battery 66 is charged and power is supplied from the photoelectric converter 64 to the power supply circuit 68. When the voltage output from the photoelectric converter 64 to the battery 66 and the power supply circuit 68 is lower than the voltage output by the battery 66, power is supplied from the battery 66 to the power supply circuit 68. When the voltage output from the photoelectric converter 64 to the battery 66 and the power supply circuit 68 is equal to the voltage output by the battery 66, power is supplied from the photoelectric converter 64 and the battery 66 to the power supply circuit 68.

[0028] The power supply circuit 68 supplies power to each of the components of the light modulation device 40, that is, the sensor interface 84, the sensor control unit 86, the modulated light generation unit 80, and the like.

[0029] The modulated light generating unit 80 includes a combiner 70, a resonance optical fiber 72, a first isolator 74-1, a filter 76, a loop splitter 78, and a second isolator 74-2. The resonance optical fiber 72 is connected between the downstream end of the combiner 70 and the upstream end of the first isolator 74-1. The downstream end of the first isolator 74-1 is connected to the upstream end of the filter 76, and the downstream end of the filter 76 is connected to the upstream end of the loop splitter 78 by optical fiber. Furthermore, one of the two downstream ends of the loop splitter 78 is connected to the upstream end of the modulation unit 88, the other of the two downstream ends of the loop splitter 78 is connected to the second isolator 74-2, and the second isolator 74-2 is connected to one of the two upstream ends of the combiner 70 by optical fiber.

[0030] The other of the two beams of light obtained by the optical branching unit 62, which is not guided to the power supply unit 30 side, is guided by an optical fiber to the other of the two upstream ends of the combiner 70 included in the modulated light generating unit 80. The combiner 70 combines the light guided from the optical branching unit 62 with the light output from the second isolator 74-2, and guides the combined light to the upstream end of the resonance optical fiber 72. The resonance optical fiber 72 may be, for example, an erbium-doped optical fiber.

[0031] Light output from the downstream end of the resonance optical fiber 72 is guided to the first isolator 74-1, and light output from the first isolator 74-1 is guided to the filter 76. The first isolator 74-1 allows light to pass from the resonance optical fiber 72 side to the filter 76 side, but attenuates or blocks light traveling in the opposite direction. The filter 76 may be, for example, a bandpass filter that attenuates and outputs light outside the 1.55 μm band. Here, the 1.55 μm band refers to light having a predetermined wavelength band that includes light with a wavelength of 1.55 μm.

[0032] The light output from the filter 76 is guided to the loop branching device 78. The loop branching device 78 branches the light output from the filter 76 into two. One of the two lights obtained by the loop branching device 78 is guided to the modulation section 88, and the other is guided to the second isolator 74-2. The second isolator 74-2 passes light from the loop branching device 78 side to the combiner 70 side, but attenuates or blocks light traveling in the opposite direction. The light output from the second isolator 74-2 is guided to the combiner 70.

[0033] With this configuration, a resonance loop 44 is formed that runs from the downstream end of the resonance optical fiber 72 through the first isolator 74-1, the filter 76, the loop splitter 78, the second isolator 74-2, and the combiner 70, and returns to the upstream end of the resonance optical fiber 72. In addition, a path is formed that excites the resonance optical fiber 72 from the optical splitter 62 via the combiner 70.

[0034] The resonance optical fiber 72 is excited by light injected from the optical branching device 62 via the multiplexer 70, and light output from the downstream end of the resonance optical fiber 72 is returned to the upstream end of the resonance optical fiber 72 via the resonance loop 44, causing the resonance optical fiber 72 to excite light. Then, light in a wavelength band selected by the filter 76 included in the resonance loop 44 is guided to the modulation unit 88. In this way, the resonance optical fiber 72 and the resonance loop 44 operate as an optical amplifier that excites light of a predetermined wavelength based on the light input from the optical branching device 62 via the multiplexer 70.

[0035] A sensor 82 is connected to a sensor interface 84 of the light modulation device 40. The sensor 82 may be a temperature sensor, a humidity sensor, an image sensor, an acceleration sensor, or the like. The sensor interface 84 outputs a detection signal output from the sensor 82 to a sensor control unit 86. The sensor interface 84 may have a function of converting the format of the detection signal output from the sensor 82 into a format compatible with the sensor control unit 86. Depending on the configuration of the sensor 82, the sensor interface 84 may have a function of converting an analog signal into a digital signal, a function of converting serial data into parallel data, or the like.

[0036] The sensor control unit 86 extracts sensor data from the detection signal and outputs it to the modulation unit 88. The modulation unit 88 generates modulated light by modulating the data transmission light output from the loop splitter 78 with the sensor data. When the sensor data is expressed in binary, the modulation process performed by the modulation unit 88 may be, for example, on / off modulation, in which light is output from the modulation unit 88 when the sensor data is high and no light is output from the modulation unit 88 when the sensor data is low. The modulation unit 88 outputs the modulated light from the output terminal 38 via the optical fiber. The data transmission optical fiber 52 connected to the output terminal 38 transmits the modulated light to the optical power supply data receiving device 10.

[0037] Returning to FIG. 2, the operation of the optically powered data receiving device 10 will be described. Modulated light transmitted through the data transmission optical fiber 52 is input to the optically powered data receiving device 10 via the receiving terminal 20. The receiving terminal 20 is connected to the photoelectric converter 22 by an optical fiber, and the modulated light input to the receiving terminal 20 is guided to the photoelectric converter 22. The photoelectric converter 22 may be configured with a photodiode. The photoelectric converter 22 converts the modulated light into electric power and outputs a modulated signal (a signal represented by voltage or current) based on that electric power to the data demodulation unit 24. Here, the modulated signal output from the photoelectric converter 22 to the data demodulation unit 24 is a signal modulated by sensor data.

[0038] The data demodulation unit 24 demodulates the modulated signal output from the photoelectric converter 22, extracts sensor data from the modulated signal, and outputs the sensor data to the control unit 26. The control unit 26 transmits the detection data via a network interface 28 to a network such as a LAN (Local Area Network) or the Internet.

[0039] In the optical power supply data transmission system 100 according to this embodiment, the optical modulation device 40 generates light in a specific wavelength band using an optical amplifier formed by a resonant optical fiber 72 and a resonant loop 44 based on light transmitted from the optical power supply data receiving device 10 to the optical modulation device 40. Furthermore, the light obtained by the optical amplifier is used as light for data transmission. That is, the optical modulation device 40 generates modulated light by modulating the light for data transmission with sensor data, and transmits the modulated light to the optical power supply data receiving device 10. Therefore, the optical modulation device 40 does not need to include a light source for generating light for data transmission, and therefore no power supply for the light source is required. This reduces energy consumption in the optical modulation device 40.

[0040] 4 shows the configuration of an optical modulation device 41 according to a second embodiment of the present invention. The optical modulation device 41 is configured by replacing the optical amplifier formed by the resonance optical fiber 72 and the resonance loop 44 in the optical modulation device 40 according to the first embodiment with a fiber laser type optical amplifier 90. The fiber laser type optical amplifier 90 includes a resonance optical fiber 92, an upstream transmission mirror 92-1 provided at the upstream end of the resonance optical fiber 92, and a downstream transmission mirror 92-2 provided at the downstream end of the resonance optical fiber 92. The resonance optical fiber 92 may be, for example, an erbium-doped optical fiber.

[0041] The downstream side of the optical splitter 62 is connected to the photoelectric converter 64 and the upstream transmission mirror 92-1 by two optical fibers that guide the two branched lights. One of the two lights obtained by the optical splitter 62 is guided to the photoelectric converter 64 by the optical fiber. The other of the two lights obtained by the optical splitter 62 is guided to the upstream transmission mirror 92-1 by the optical fiber.

[0042] Light incident on the upstream transmission mirror 92-1 from the optical branching device 62 is incident on the resonance optical fiber 92 via the upstream transmission mirror 92-1. The light incident on the resonance optical fiber 92 propagates to the downstream end, where a portion of it is reflected upstream at the downstream transmission mirror 92-2, and the remaining portion is reflected upstream. The light reflected upstream propagates to the upstream end of the resonance optical fiber 92, is reflected downstream at the upstream transmission mirror 92-1, and propagates to the downstream end. As a result, the light is multiple-reflected between the upstream transmission mirror 92-1 and the downstream transmission mirror 92-2, and a portion of the light that reaches the downstream transmission mirror 92-2 from the upstream side is transmitted through the downstream transmission mirror 92-2 toward the optical fiber leading to the modulation unit 88. As a result, light having a specific wavelength is excited by the fiber laser optical amplifier 90 and input to the modulation unit 88 via the optical fiber. [Explanation of symbols]

[0043] 10 Optical power supply data receiving device, 12 Laser diode control unit, 14 Laser diode, 18 Transmission terminal, 20 Receiving terminal, 22 Photoelectric converter, 24 Data demodulation unit, 26 Control unit, 28 Network interface, 30 Power supply unit, 40, 41 Optical modulation device, 42 Sensor, 44 Resonance loop, 50 Power supply optical fiber, 52 Data transmission optical fiber, 60 Input terminal, 62 Optical branching unit, 64 Photoelectric converter, 66 Battery, 68 Power supply circuit, 70 Combiner, 72, 92 Resonance optical fiber, 74-1 First isolator, 74-2 Second isolator, 76 Filter, 78 Loop branching unit, 80 Modulated light generation unit, 82 Sensor, 84 Sensor interface, 86 Sensor control unit, 88 Modulation unit, 90 Fiber laser type optical amplifier, 94-1 Upstream transmission mirror, 94-2 Downstream transmission mirror, 100 Optically powered data transmission system.

Claims

1. an optical splitter that splits input light into two; a power supply unit that converts one of the two lights obtained by the optical branching unit into electric power; a modulation unit that modulates the other of the two beams obtained by the optical branching unit with data to be transmitted to generate modulated light, The optical modulation device is characterized in that the power supply unit supplies power to the modulation unit.

2. 2. The optical modulation device according to claim 1, an optical amplifier that excites light of a predetermined wavelength based on the other of the two lights obtained by the optical branching device; The modulation unit An optical modulation device that modulates light excited by the optical amplifier.

3. 3. The optical modulation device according to claim 2, The optical amplifier comprises: a resonance optical fiber; a resonance loop extending from the downstream end of the resonance optical fiber back to the upstream end thereof.

4. 3. The optical modulation device according to claim 2, The optical amplifier comprises: a resonance optical fiber; an upstream transmission mirror provided at the upstream end of the resonance optical fiber; a downstream transmission mirror provided at the downstream end of the resonance optical fiber; An optical modulation device comprising:

5. 5. The optical modulation device according to claim 3, The resonance optical fiber is An optical modulation device characterized by being an erbium-doped optical fiber.

6. 5. The optical modulation device according to claim 1, The power supply unit an opto-electrical converter that converts one of the two lights obtained by the optical branching device into electric power; a battery that is charged by the power output from the photoelectric converter; An optical modulation device, wherein power is output from at least one of the photoelectric converter and the battery.

7. 5. The optical modulation device according to claim 1, a sensor control unit connected to the sensor and generating sensor data including a detection value of the sensor; The modulation unit An optical modulation device characterized in that the other of the two beams obtained by the optical branching device is modulated by the sensor data.

8. The optical modulation device according to any one of claims 1 to 4, an input terminal provided in the optical modulation device and into which the input light is input; an output terminal provided in the optical modulation device and configured to output the modulated light; an optical transmitter that outputs light for energy supply to an upstream end of a power supply optical fiber whose downstream end is connected to the input terminal; a data demodulation unit that acquires the modulated light from a downstream end of a data transmission optical fiber whose upstream end is connected to the output terminal, and demodulates the modulated light to extract the data; An optical power supply data transmission system comprising:

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