JP2005198396A - Optical power supply system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical power supply system which can supply a large power by realizing an efficient optical transmission with simple configuration. <P>SOLUTION: An energy is transmitted from a center station 2A to a user station 4 by a light, and converted into the power. The center station 2A includes a plurality of light sources. The lights from the respective light sources are divided into a plurality so that the intensities of the respective lights become less than a nonlinear boundary. The divided lights are multiplexed at the output parts of the plurality of the light sources and sent to the user station 4 by a plurality of optical fibers 6.1-6.N, and a large power can be outputted from the lights. Since the light sources are different even if the divided lights are multiplexed, an interference does not occur, and the intensities do not exceed the nonlinear boundary. Therefore, the transmission loss of the energy via the optical fiber can be reduced. Preferably, the plurality of the light sources which output the lights having different wavelengths, are used. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical power feeding system that transmits energy through an optical fiber to perform power feeding.

  In optical power feeding, power is supplied to an optical communication terminal device, a remote sensor, or the like through an optical fiber, thereby eliminating the need for a metal core for power supply or securing a local power supply.

  An optical power feeding system that feeds power through an optical fiber has been proposed for a long time because it only requires an optical fiber connection and no electrical wiring work is required. This optical power supply device generates light energy by a powerful light source on the power supply side, transmits this light energy through an optical fiber, and photoelectrically converts it by a photodiode or solar cell on the power supply side, thereby converting it into electric energy. Configured to convert.

For example, Japanese Patent Laid-Open No. 5-268191 (Patent Document 1) discloses a technique related to optical power feeding that improves the transmission efficiency of optical power by polarization multiplexing multiplexing light. Japanese Patent Laid-Open No. 5-268192 (Patent Document 2) discloses a technique related to optical power feeding that improves the output voltage after light reception by an optical reception method.
JP-A-5-268191 Japanese Patent Laid-Open No. 5-268192

  In such an optical power supply system, a loss in a light source that generates light with electric power on the power supply side and a loss due to optical-electrical conversion on the power supply side occur. Various improvements have been proposed to reduce such losses and improve efficiency.

  FIG. 8 is a diagram showing a configuration of a conventional optical power feeder disclosed in Japanese Patent Laid-Open No. 5-268191 (Patent Document 1).

  In FIG. 8, in order to increase the power to be transmitted, n laser diodes 111 to 110. n is used. The laser beams having wavelengths λ1 to λn are merged by the merger 115, polarized by the polarization controller 111, and transmitted through the constant polarization fiber 112.

  The laser beam transmitted to the power supply side is demultiplexed by the demultiplexer 116 into laser beams having wavelengths λ1 to λn each having two polarization components. Then, the two polarization components of each laser beam are respectively beam splitters 113.1 to 113. n are separated and photoelectrically converted by each pair of laser diodes (PD11, PD12) to (PDn1, PDn2).

  However, in optical power feeding using an optical fiber, energy concentrates and propagates in a thin core of the optical fiber. When the intensity of light passing through the optical fiber exceeds a certain threshold value, a non-linear phenomenon occurs, and therefore a loss occurs. In particular, non-linear phenomena are likely to occur when transmitting a large amount of light with a single mode fiber for optical communication.

  Non-linear phenomena include, for example, Brillouin scattering caused by the interaction of incident light and sound waves generated in the core glass. In order to efficiently supply a large amount of power, it is necessary to reduce such loss in the optical transmission line.

  An object of the present invention is to provide an optical power feeding system capable of realizing efficient optical wavelength division multiplexing transmission with a simple configuration and supplying large electric power.

  In summary, the present invention is an optical power feeding system, which is connected to a plurality of light sources, a plurality of first optical fibers that respectively transmit light output from the plurality of light sources, and a plurality of first optical fibers. An optical coupler that multiplexes the light transmitted by the plurality of first optical fibers, branches and outputs the plurality of multiplexed lights, and one end of each is connected to the output of the optical coupler, and a plurality of multiplexed lights And a plurality of second optical fibers that respectively transmit the light and power generation means that receives the light output from the other ends of the plurality of second optical fibers and generates power.

  Preferably, each of the plurality of light sources outputs light having an intensity exceeding a nonlinear boundary of the second optical fiber, each of the plurality of second optical fibers being longer than the first optical fiber, Multiplexed light transmitted by each of the second optical fibers includes a plurality of lights each having an intensity that is less than the nonlinear boundary.

  Preferably, the power generation means includes a plurality of conversion means attached to the other ends of the plurality of second optical fibers, respectively, for converting light into electric power.

  More preferably, the outputs of a plurality of conversion means are collected and supplied to one user.

  More preferably, the plurality of conversion units are arranged at positions separated from each other, and each supply power to a plurality of users.

  Preferably, the optical coupler includes an optical fiber coupler having an input connected to the plurality of first optical fibers and an output connected to the plurality of second optical fibers.

  Preferably, the plurality of lights output from the plurality of light sources respectively have different wavelengths.

  According to the present invention, an energy transmission loss in an optical fiber is reduced, and an efficient optical power feeding system can be realized. Further, by using an optical fiber coupler as an optical coupler, an inexpensive and simple configuration can be achieved. Furthermore, even when a failure occurs in one of the plurality of light sources, the supply power is reduced, but it is possible to prevent the supply of power to a part of the user from being interrupted.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol in a figure shows the same or an equivalent part.

[Embodiment 1]
FIG. 1 is a diagram showing the configuration of the optical power feeding system according to Embodiment 1 of the present invention.

  Referring to FIG. 1, an optical power feeding system 1 includes a center station 2 that is connected to a power source and outputs light, a user station 4 that receives light from the center station, and an optical fiber that connects the center station 2 and the user station 4. Cable 6 is included.

  The center station 2 has a plurality of light sources 10.1 to 10. N and light sources 10.1-10. N to single-core optical fibers 11.1 to 11. N and optical fibers 11.1 to 11. And an optical coupler 12 that couples the light transmitted by N and sends it to the optical fiber cable 6.

  The optical fiber cable 6 is a multi-core cable, and N optical fibers 6.1 to 6. N is included. In the optical coupler 12, N optical fibers are connected to the input, and the N optical fibers 6.1 to 6. N is an N-to-N coupler connected to the output.

  The user station 4 has optical fibers 6.1 to 6. N are respectively connected to the photoelectric converters 14.1 to 14. N and photoelectric converters 14.1 to 14. And a load 15 that receives power converted from light by N.

  Photoelectric converters 14.1-14. Each of N converts input light into electric power, and for example, a solar cell is used for this.

  As shown in FIG. 1, N optical fibers 6.1 to 6. The light of each light source is transmitted to each N with an intensity of approximately 1 / N. As the light source, a laser for power use, for example, a pump laser is used. Since the intensity per light becomes low, the nonlinear phenomenon in the optical fiber hardly occurs.

  In an optical cable, an optical fiber core is often configured to be accommodated as a tape core in which four or eight optical fibers are flatly bundled into a tape shape. In general, optical fibers are connected in units of tape. For this reason, if N is set to 4 or 8, it is a system in which light is transmitted by one tape, so that it is a natural form for construction and the work is also simple.

  Here, since light from a plurality of light sources is incident on one fiber, the light intensity once lowered individually is increased again by the interaction of the plurality of lights, and a nonlinear phenomenon occurs. Concerns arise.

  However, since the light is not from the same light source but from different light sources, the coherence is low and the nonlinear phenomenon is less likely to occur. A laser for power use does not necessarily have high accuracy of wavelength of an individual element like a laser for communication, and the wavelength of output light is often different for each individual element. Therefore, it is unlikely that light emitted from a plurality of lasers for power applications interferes in the optical fiber and increases in intensity, causing a nonlinear phenomenon. Further, even if the wavelength is the same, if the phase is different, it is difficult to cause interference, so that a nonlinear phenomenon is unlikely to occur.

  That is, if the light is output from different light sources, the transmission loss of the optical fiber can be reduced even if the output light has the same wavelength. This is because light output from different light sources is unlikely to have the same phase even if they have close wavelengths, and nonlinear phenomena in the optical fiber are unlikely to occur.

  Therefore, even if the intensity of light output from each light source is such that the nonlinearity occurs at a short distance from the light source to the optical coupler 12, each light source in the optical fiber cable 6 that transmits a long distance is used. Since the light from the light has an intensity of approximately 1 / N and is mixed and transmitted through each optical fiber, transmission loss in the optical fiber cable 6 can be reduced. In this case, although the light intensity is low and the nonlinear phenomenon is less likely to occur, the total amount of transmitted light energy does not change before and after the optical coupler 12.

  The transmitted light is converted into photoelectric converters 14.1-14. A large amount of power can be supplied to the load 15 by converting the power into power by N and summing these powers. 1 shows an example in which a plurality of photoelectric converters are provided, but the optical fibers 6.1 to 6. N may be bundled to irradiate one photoelectric converter with light to convert it into electric power. At that time, the light may be condensed via a lens or the like and supplied to the photoelectric converter.

  When a plurality of photoelectric converters are provided, the current value can be increased by connecting them in parallel, and a high voltage can be obtained by connecting them in series. You may use a part of photoelectric converter for another load as needed.

  FIG. 2 is a diagram showing a modification of the optical power feeding system in FIG.

  Referring to FIG. 2, optical power supply system 1 </ b> A includes a center station 2 </ b> A instead of center station 2 in the configuration of optical power supply system 1 shown in FIG. 1.

  The center station 2A has light sources 10.1 to 10 in the configuration of the center station 2 in FIG. N, respectively, instead of the light sources 10A. 1-10A. N is included.

  Light source 10A. 1-10A. N outputs light having different wavelengths λ1 to λN. Since the other configuration of optical power feeding system 1A is the same as that of optical power feeding system 1 shown in FIG. 1, description thereof will not be repeated.

  In the case of FIG. 1, when the spectrums of the light output from some of the light sources overlap by chance, interference may occur and the light intensity may exceed the nonlinear boundary. However, as shown in FIG. 2, interference can be made difficult to occur by using a plurality of light sources that output light of different wavelengths. Therefore, the transmission loss in the optical fiber cable 6 can be further reliably reduced.

  As the optical coupler 12 in FIGS. 1 and 2, an optical fiber coupler can be used. Optical fiber couplers are cheaper than using other optical couplers and splitting their outputs.

  FIG. 3 is a diagram for explaining the optical fiber coupler.

  An optical fiber coupler bundles a plurality of optical fibers and fuses the bundled portions to bring the cores of the optical fibers close to each other, thereby causing mode coupling of the respective optical fibers and branching the light power from one to the other. This is an optical coupler. In the example shown in FIG. 3, some of the two optical fibers are fused and stretched. Light incident from the input end 21 is output from both the output ends 23 and 24. At that time, the intensity of light decreases according to the number of branches. Such optical fiber couplers have many more inputs and outputs. Such an optical fiber coupler is called an optical fiber star coupler.

  FIG. 4 is a view showing the appearance of the optical fiber star coupler.

  As shown in FIG. 4, when light having different wavelengths λ1 to λN is input from N inputs, light having wavelengths λ1 to λN is mixed and output from the N outputs. At that time, the intensity of light of each wavelength per optical fiber is approximately 1 / N.

  FIG. 5 is a diagram for explaining one of the input lights in FIG.

  Referring to FIG. 5, the input light is strong light exceeding the intensity of the nonlinear boundary, for example, 50 mW. Although FIG. 5 shows only the light with the wavelength λ1 as an example, the light with the other wavelengths λ2 to λN has the same intensity.

  FIG. 6 is a diagram for explaining light in one optical fiber out of the light output from the optical fiber star coupler of FIG.

  Referring to FIG. 6, for one of N pieces connected to the output side, a plurality of light components that do not exceed the nonlinear boundary strength, for example, 50 mW, are incident on each optical fiber. As a result, the optical fiber transmission loss was large due to the nonlinearity phenomenon because the nonlinearity boundary was exceeded on the input side, but loss of optical transmission due to the nonlinearity phenomenon is less likely to occur even if the total optical energy is the same on the output side. Become.

  As described above, the optical power feeding system according to the first embodiment transmits energy from the center station 2A to the user station 4 by light and converts it into electric power. The center station 2A includes a plurality of light sources. The light from each light source is divided into a plurality so that each light intensity is less than the nonlinear boundary. The divided light is multiplexed with the output of a plurality of light sources, and a plurality of optical fibers 6.1 to 6. N is sent to the user station 4 and a large amount of power can be extracted from this light. Since the light sources are different even when multiplexed, the interference does not occur and the intensity does not exceed the nonlinear boundary. Therefore, energy transmission loss due to the optical fiber can be reduced. Preferably, a plurality of light sources that emit light having different wavelengths are used.

[Embodiment 2]
FIG. 7 is a diagram illustrating a configuration of the optical power feeding system 30 according to the second embodiment.

  Referring to FIG. 7, the optical power feeding system 30 includes a center station 2 and a plurality of user stations 31.1 to 31. N, the center station 2 and the user stations 31.1 to 31. N to optical fibers 6.1 to 6. N. Optical fibers 6.1-6. N is grouped as an optical fiber cable 6 until halfway.

  Since center station 2 has the same configuration as that shown in FIG. 1, description thereof will not be repeated. Further, instead of the center station 2, the center station 2A shown in FIG.

  User stations 31.1 to 31. N represents photoelectric converters 32.1 to 32. N and loads 33.1 to 33. receiving power supplied from the photoelectric converter. N.

  In this way, N optical fibers on the output side can be distributed to N points, and energy can be transmitted to N users.

  As described above, by using the present invention, it is possible to reduce transmission loss due to a nonlinear phenomenon in an optical fiber. Furthermore, in a star network or a sensor network that provides services from the center station to each user station, a 1-to-N power supply is required, and this case is effective.

  In addition, compared to the case where light is transmitted from one light source to one user without providing an optical coupler, the power supply is reduced even when a failure occurs in one of the plurality of light sources, but the user is reduced. It is possible to prevent the supply of electric power from being interrupted for a part of the battery.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is the figure which showed the structure of the optical power feeding system of Embodiment 1 of this invention. It is the figure which showed the modification of the optical power feeding system in FIG. It is a figure for demonstrating an optical fiber coupler. It is the figure which showed the external appearance of the optical fiber star coupler. It is a figure explaining one of the input lights in FIG. It is a figure for demonstrating the light in one optical fiber among the lights output from the optical fiber coupler of FIG. 5 is a diagram illustrating a configuration of an optical power feeding system 30 according to a second embodiment. FIG. It is a figure which shows the structure of the conventional optical power feeder disclosed by Unexamined-Japanese-Patent No. 5-268191 (patent document 1).

Explanation of symbols

  1, 1A, 30 Optical power feeding system, 2, 2A Center station, 4 User station, 6 Optical fiber cable, 6.1-6. N optical fiber, 10, 10A light source, 10.1-10. N, 11.1-11. N optical fiber, 12 optical coupler, 14.1-14. N, 32.1-32. N photoelectric converter, 15, 33 load, 21 input end, 23 output end, 31 user station.

Claims (8)

Multiple light sources;
A plurality of first optical fibers that respectively transmit light output from the plurality of light sources;
An optical coupler connected to the plurality of first optical fibers, multiplexing the light transmitted by the plurality of first optical fibers, and branching and outputting the plurality of multiplexed lights;
A plurality of second optical fibers each having one end connected to the output of the optical coupler and respectively transmitting the plurality of multiplexed lights;
An optical power feeding system comprising: power generation means that receives the light output from the other end of the plurality of second optical fibers and generates power. Each of the plurality of light sources outputs light having an intensity exceeding a limit light intensity at which a nonlinear effect due to light occurs in the second optical fiber,
Each of the plurality of second optical fibers is longer than the first optical fiber,
The optical power feeding system according to claim 1, wherein the multiplexed light transmitted by each of the plurality of second optical fibers includes a plurality of lights each having an intensity less than a nonlinear boundary. The power generation means includes
2. The optical power feeding system according to claim 1, further comprising a plurality of conversion units that are respectively attached to the other ends of the plurality of second optical fibers and convert light into electric power.   The optical power feeding system according to claim 3, wherein outputs of the plurality of converting units are collected and fed to one user.   The optical power feeding system according to claim 3, wherein the plurality of conversion units are arranged at positions separated from each other, and each supply electric power to a plurality of users. The optical coupler is
The optical power feeding system according to claim 1, comprising an optical fiber coupler having an input connected to the plurality of first optical fibers and an output connected to the plurality of second optical fibers.   The optical power feeding system according to claim 1, wherein the plurality of lights output from the plurality of light sources have different wavelengths.   2. The power generation unit according to claim 1, wherein the power generation unit collects the other ends of the plurality of second optical fibers, collects light transmitted through each of the plurality of second optical fibers, and converts the light into electric power. Optical power supply system.

Images