Patent Publication Number: US-2022239157-A1

Title: Power over fiber system and feed light visualization lid member

Description:
RELATED APPLICATIONS 
     The present application is a National Phase of International Application No. PCT/JP2020/020616 filed May 25, 2020, which claims priority to Japanese Application No. 2019-105978, filed Jun. 6, 2019. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to optical power supply. 
     BACKGROUND ART 
     Recently, there has been studied an optical power supply system that converts electric power into light (called feed light), transmits the feed light, converts the feed light into electric energy, and uses the electric energy as electric power. 
     There is disclosed in Patent Literature 1 an optical communication device that includes: an optical transmitter that transmits signal light modulated with an electric signal and feed light for supplying electric power; an optical fiber including a core that transmits the signal light, a first cladding that is formed around the core, has a refractive index lower than that of the core, and transmits the feed light, and a second cladding that is formed around the first cladding, and has a refractive index lower than that of the first cladding; and an optical receiver that operates with electric power obtained by converting the feed light transmitted through the first cladding of the optical fiber, and converts the signal light transmitted through the core of the optical fiber into the electric signal. 
     CITATION LIST 
     Patent Literature 
     Patent Literature 1: JP 2010-135989 A 
     SUMMARY OF INVENTION 
     Problem to Solve 
     By the way, if invisible light beams are used as feed light, a user or the like cannot easily determine whether the feed light is being released to the outside. 
     In optical power supply, transmission of higher energy light is expected. 
     An optical power supply system using a high-power laser for power supply may cause injuries or accidents by a user or the like handling an optical fiber or another module thereof without being aware of release of feed light. Such accidents are desired to be prevented. 
     Solution to Problem 
     A power over fiber system according to an aspect of the present disclosure includes: 
     a power sourcing equipment including a semiconductor laser that oscillates with electric power, thereby outputting feed light; 
     a powered device including a photoelectric conversion element that converts the feed light output by the power sourcing equipment into electric power; and 
     an optical fiber cable that transmits the feed light from the power sourcing equipment to the powered device, 
     wherein the feed light is invisible light, 
     wherein the power over fiber system further comprises an openable/closeable or attachable/detachable lid member that covers an outgoing portion from which the feed light goes out, and 
     wherein at least part of a light receiving portion of the lid member, the light receiving portion receiving the feed light, is made of a wavelength conversion material that converts a wavelength of the feed light into a wavelength of visible light. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a block diagram of a power over fiber system according to a first embodiment of the present disclosure. 
         FIG. 2  is a block diagram of a power over fiber system according to a second embodiment of the present disclosure. 
         FIG. 3  is a block diagram of the power over fiber system according to the second embodiment of the present disclosure and shows optical connectors and so forth. 
         FIG. 4  is a block diagram of a power over fiber system according to another embodiment of the present disclosure. 
         FIG. 5  is a schematic view showing a configuration in which an optical connector of a power sourcing equipment has a lid member. 
         FIG. 6  is a schematic view showing a configuration in which an optical connector at an end of an optical fiber cable has a lid member. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. 
     (1) Outline of System 
     First Embodiment 
     As shown in  FIG. 1 , a power over fiber (PoF) system  1 A of this embodiment includes a power sourcing equipment (PSE)  110 , an optical fiber cable  200 A and a powered device (PD)  310 . 
     In the present disclosure, a power sourcing equipment converts electric power into optical energy and supplies (sources) the optical energy, and a powered device receives (draws) the supplied optical energy and converts the optical energy into electric power. 
     The power sourcing equipment  110  includes a semiconductor laser  111  for power supply. 
     The optical fiber cable  200 A includes an optical fiber  250 A that forms a transmission path of feed light. 
     The powered device  310  includes a photoelectric conversion element  311 . 
     The power sourcing equipment  110  is connected to a power source, and electrically drives the semiconductor laser  111  and so forth. 
     The semiconductor laser  111  oscillates with the electric power from the power source, thereby outputting feed light  112 . 
     The optical fiber cable  200 A has one end  201 A connectable to the power sourcing equipment  110  and the other end  202 A connectable to the powered device  310  to transmit the feed light  112 . 
     The feed light  112  from the power sourcing equipment  110  is input to the one end  201 A of the optical fiber cable  200 A, propagates through the optical fiber  250 A, and is output from the other end  202 A of the optical fiber cable  200 A to the powered device  310 . 
     The photoelectric conversion element  311  converts the feed light  112  transmitted through the optical fiber cable  200 A into electric power. The electric power obtained by the conversion of the feed light  112  by the photoelectric conversion element  311  is driving power needed in the powered device  310 . The powered device  310  is capable of outputting, for an external device(s), the electric power obtained by the conversion of the feed light  112  by the photoelectric conversion element  311 . 
     Semiconductor materials of semiconductor regions of the semiconductor laser  111  and the photoelectric conversion element  311  are semiconductors having a laser wavelength being a short wavelength of 500 nm or less. The semiconductor regions exhibit light-electricity conversion effect. 
     Semiconductors having a laser wavelength being a short wavelength have a large band gap and a high photoelectric conversion efficiency, and hence improve photoelectric conversion efficiency at the power supplying side and the power receiving side in optical power supply, and improve optical power supply efficiency. 
     Hence, as the semiconductor materials, laser media having a laser wavelength (base wave) of 200 nm to 500 nm may be used. Examples thereof include diamond, gallium oxide, aluminum nitride and gallium nitride. 
     Further, as the semiconductor materials, semiconductors having a band gap of 2.4 eV or greater are used. 
     For example, laser media having a band gap of 2.4 eV to 6.2 eV may be used. Examples thereof include diamond, gallium oxide, aluminum nitride and gallium nitride. 
     Laser light having a longer wavelength tends to have a higher transmission efficiency, whereas laser light having a shorter wavelength tends to have a higher photoelectric conversion efficiency. Hence, when laser light is transmitted for a long distance, laser media having a laser wavelength (base wave) of greater than 500 nm may be used as the semiconductor materials, whereas when the photoelectric conversion efficiency is given priority, laser media having a laser wavelength (base wave) of less than 200 nm may be used as the semiconductor materials. 
     Any of these semiconductor materials may be used in one of the semiconductor laser  111  and the photoelectric conversion element  311 . This improves the photoelectric conversion efficiency at either the power supplying side or the power receiving side, and improves the optical power supply efficiency. 
     Second Embodiment 
     As shown in  FIG. 2 , a power over fiber (PoF) system  1  of this embodiment includes a power supply system through an optical fiber and an optical communication system therethrough, and includes: a first data communication device  100  including a power sourcing equipment (PSE)  110 ; an optical fiber cable  200 ; and a second data communication device  300  including a powered device (PD)  310 . 
     The power sourcing equipment  110  includes a semiconductor laser  111  for power supply. The first data communication device  100  includes, in addition to the power sourcing equipment  110 , a transmitter  120  and a receiver  130  for data communication. The first data communication device  100  corresponds to a data terminal equipment (DTE), a repeater or the like. The transmitter  120  includes a semiconductor laser  121  for signals and a modulator  122 . The receiver  130  includes a photodiode  131  for signals. 
     The optical fiber cable  200  includes an optical fiber  250  including: a core  210  that forms a transmission path of signal light; and a cladding  220  that is arranged so as to surround the core  210  and forms a transmission path of feed light. 
     The powered device  310  includes a photoelectric conversion element  311 . The second data communication device  300  includes, in addition to the powered device  310 , a transmitter  320 , a receiver  330  and a data processing unit  340 . The second data communication device  300  corresponds to a power end station or the like. The transmitter  320  includes a semiconductor laser  321  for signals and a modulator  322 . The receiver  330  includes a photodiode  331  for signals. The data processing unit  340  processes received signals. The second data communication device  300  is a node in a communication network. The second data communication device  300  may be a node that communicates with another node. 
     The first data communication device  100  is connected to a power source, and electrically drives the semiconductor laser  111 , the semiconductor laser  121 , the modulator  122 , the photodiode  131  and so forth. The first data communication device  100  is a node in a communication network. The first data communication device  100  may be a node that communicates with another node. 
     The semiconductor laser  111  oscillates with the electric power from the power source, thereby outputting feed light  112 . 
     The photoelectric conversion element  311  converts the feed light  112  transmitted through the optical fiber cable  200  into electric power. The electric power obtained by the conversion of the feed light  112  by the photoelectric conversion element  311  is driving power needed in the second data communication device  300 , for example, driving power for the transmitter  320 , the receiver  330  and the data processing unit  340 . The second data communication device  300  may be capable of outputting, for an external device(s), the electric power obtained by the conversion of the feed light  112  by the photoelectric conversion element  311 . 
     The modulator  122  of the transmitter  120  modulates laser light  123  output by the semiconductor laser  121  to signal light  125  on the basis of transmission data  124 , and outputs the signal light  125 . 
     The photodiode  331  of the receiver  330  demodulates the signal light  125  transmitted through the optical fiber cable  200  to an electric signal, and outputs the electric signal to the data processing unit  340 . The data processing unit  340  transmits data of the electric signal to a node, and also receives data from the node and outputs the data to the modulator  322  as transmission data  324 . 
     The modulator  322  of the transmitter  320  modulates laser light  323  output by the semiconductor laser  321  to signal light  325  on the basis of the transmission data  324 , and outputs the signal light  325 . 
     The photodiode  131  of the receiver  130  demodulates the signal light  325  transmitted through the optical fiber cable  200  to an electric signal, and outputs the electric signal. Data of the electric signal is transmitted to a node, whereas data from the node is the transmission data  124 . 
     The feed light  112  and the signal light  125  from the first data communication device  100  are input to one end  201  of the optical fiber cable  200 , propagate through the cladding  220  and the core  210 , respectively, and are output from the other end  202  of the optical fiber cable  200  to the second data communication device  300 . 
     The signal light  325  from the second data communication device  300  is input to the other end  202  of the optical fiber cable  200 , propagates through the core  210 , and is output from the one end  201  of the optical fiber cable  200  to the first data communication device  100 . 
     As shown in  FIG. 3 , the first data communication device  100  includes a light input/output part  140  and an optical connector  141  attached to the light input/output part  140 , and the second data communication device  300  includes a light input/output part  350  and an optical connector  351  attached to the light input/output part  350 . An optical connector  230  provided at the one end  201  of the optical fiber cable  200  is connected to the optical connector  141 , and an optical connector  240  provided at the other end  202  of the optical fiber cable  200  is connected to the optical connector  351 . The light input/output part  140  guides the feed light  112  to the cladding  220 , guides the signal light  125  to the core  210 , and guides the signal light  325  to the receiver  130 . The light input/output part  350  guides the feed light  112  to the powered device  310 , guides the signal light  125  to the receiver  330 , and guides the signal light  325  to the core  210 . 
     As described above, the optical fiber cable  200  has the one end  201  connectable to the first data communication device  100  and the other end  202  connectable to the second data communication device  300  to transmit the feed light  112 . In this embodiment, the optical fiber cable  200  transmits the signal light  125 ,  325  bidirectionally. 
     As the semiconductor materials of the semiconductor regions, which exhibit the light-electricity conversion effect, of the semiconductor laser  111  and the photoelectric conversion element  311 , any of those described in the first embodiment can be used, thereby achieving a high optical power supply efficiency. 
     Like an optical fiber cable  200 B of a power over fiber system  1 B shown in  FIG. 4 , an optical fiber  260  that transmits signal light and an optical fiber  270  that transmits feed light may be provided separately. Further, the optical fiber cable  200 B may be composed of a plurality of optical fiber cables. 
     (2) Embodiments of Lid Member 
     Next, embodiments of a lid member will be described with reference to  FIG. 5  and  FIG. 6 . 
     Assume that the feed light  112  is invisible light. 
     Application of a high-power semiconductor laser  111  for power supply may cause injuries or accidents by a user or the like handling an optical fiber or another module without being aware of release of the feed light  112 . 
     Hence, as shown in  FIG. 5  or  FIG. 6 , an openable/closable or attachable/detachable lid member  410 / 420  that covers an outgoing portion from which the feed light  112  goes out is provided. 
       FIG. 5  shows a configuration in which, as the lid member, a lid member  410  covering a feed light outgoing portion (opening of the optical connector  141 ) of the power sourcing equipment  110  is provided.  FIG. 6  shows a configuration in which, as the lid member, a lid member  420  covering a feed light outgoing portion (opening of the optical connector  240 ) of the optical fiber cable  200  is provided. 
     At least part of a light receiving portion of the lid member  410 / 420 , the light receiving portion receiving the feed light  112 , is made of a wavelength conversion material  411 / 421 , such as a fluorescent material, which converts the wavelength of the feed light  112  into a wavelength of visible light. 
     Hence, if, as shown in  FIG. 5 , the optical connector  230  is disconnected from the optical connector  141  and output of the feed light  112  is not stopped, the feed light  112  is released to the outside as visible light  401  into which the feed light  112  has been converted by the wavelength conversion material  411 . 
     This enables the user or the like to find, at an early stage, with his/her eyes that the feed light  112  is being output and take measures, for example, stop the output of the feed light  112 , to prevent injuries or accidents. 
     Further, if the optical fiber cable  200  is connected to the first data communication device  100  at the power supplying side, and, as shown in  FIG. 6 , the optical connector  240  is not connected to the optical connector  351  and output of the feed light  112  is not stopped, the feed light  112  is released to the outside as visible light  401  into which the feed light  112  has been converted by the wavelength conversion material  421 . 
     This enables the user or the like to find, at an early stage, with his/her eyes that the feed light  112  is being output and take measures, for example, stop the output of the feed light  112 , to prevent injuries or accidents. 
     The lid member  410 / 420  may be embodied in an attachable/detachable form, such as a cap, or may be embodied in an openable/closable form, such as a lid member connected to and supported by the connector  141  ( 240 ). 
     Although some embodiments of the present disclosure have been described above, these embodiments are made for purposes of illustration and example only. The present invention can be carried out in various other forms, and each component may be omitted, replaced or modified/changed within a range not departing from the scope of the present invention. 
     The above (2) has been described with the second embodiment as the basis, but it is a matter of course that the same is applicable to the first embodiment, where components of an optical communication system are excluded. 
     INDUSTRIAL APPLICABILITY 
     The present invention is applicable to a power over fiber system and a feed light visualization lid member.