Optical repeater and optical communication system

Abstract

Provided is an optical repeater that reduces voltage consumption and maintains robustness against control unit failures. An optical repeater (100) according to the present disclosure comprises: two units, each of which comprises a light emitter, an optical demultiplexer, an optical multiplexer, a wavelength-division multiplexing coupler, and an optical amplifier; a control unit A (101) that controls a light emitter LDA1 of one unit; and a control unit B (102) that controls a light emitter LDB1 of the other unit. Optical demultiplexers CA11 and CB11 split light output from the light emitters LDA1 and LDB1, respectively, and supply the split light to the optical multiplexer of each unit. Optical multiplexers CA21 and CB21 multiplex supplied light and respectively supply the multiplexed light to the wavelength-division multiplexing coupler of each unit. The wavelength-division multiplexing couplers each combine the supplied light with an optical signal, and supply the combined light to the optical amplifier of the same unit.

Description

[Technical Field]

[0001] The present disclosure relates to an optical repeater and an optical communication system. [Background technology]

[0002] In optical communication systems for long-distance transmission, such as submarine optical cable systems, multiple optical repeaters are inserted into the transmission path to electrically compensate for the attenuation of optical signals. The optical repeater has an optical amplifier that amplifies the optical signal, and an erbium-doped fiber amplifier (EDFA) or the like that can directly amplify the optical signal is used as such an optical amplifier.

[0003] In an optical communication system, the influence of voltage drop in optical repeaters increases as the number of optical repeaters inserted increases, so there is a demand for suppression of voltage drop inside optical repeaters.

[0004] One method for suppressing voltage drops in optical repeaters is to reduce the voltage consumption of the optical repeater. Patent Document 1 discloses an optical repeater in which one control unit controls an excitation light source having two light-emitting elements, i.e., the number of control units controlling the excitation light source is reduced. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2019 / 176205 Summary of the Invention [Problem to be solved by the invention]

[0006] The method of reducing the voltage consumption of an optical amplifier by increasing the number of pumping light sources controlled by one control unit is a trade-off with the robustness of the optical amplifier, because if the control unit fails, the number of pumping light sources that stop functioning will also increase.

[0007] In view of the above, an object of the present disclosure is to provide an optical repeater that reduces voltage consumption and maintains robustness against failures in the control unit. [Means for solving the problem]

[0008] An optical repeater according to the present disclosure comprises a first unit including a first light-emitting element, a first optical demultiplexer, a first optical multiplexer, a first wavelength division multiplexing coupler, and a first optical amplifier, a second unit including a second light-emitting element, a second optical demultiplexer, a second optical multiplexer, a second wavelength division multiplexing coupler, and a second optical amplifier, a first control unit that controls the first light-emitting element, and a second control unit that controls the second light-emitting element. The first optical demultiplexer branches light output from the first light-emitting element and supplies the branched light to the first optical multiplexer and the second optical multiplexer, respectively, and the second optical demultiplexer branches light output from the second light-emitting element and supplies the branched light to the first optical multiplexer and the second optical multiplexer, respectively. The first optical multiplexer multiplexes the light supplied from the first optical demultiplexer and the second optical demultiplexer and supplies the multiplexed light to the first wavelength division multiplexing coupler, the second optical multiplexer multiplexes the light supplied from the first optical demultiplexer and the second optical demultiplexer and supplies the multiplexed light to the second wavelength division multiplexing coupler, the first wavelength division multiplexing coupler multiplexes the light multiplexed by the first optical multiplexer with a first optical signal and supplies the multiplexed light to the first optical amplifier, and the second wavelength division multiplexing coupler multiplexes the light multiplexed by the second optical multiplexer with a second optical signal and supplies the multiplexed light to the second optical amplifier.

[0009] The optical communication system according to the present disclosure includes an optical transmitter that transmits an optical signal, an optical receiver that receives the optical signal, an optical fiber that transmits the optical signal, and an optical repeater inserted into the optical fiber. The optical repeater includes a first unit that includes a first light-emitting element, a first optical demultiplexer, a first optical multiplexer, a first wavelength division multiplexing coupler, and a first optical amplifier, a second unit that includes a second light-emitting element, a second optical demultiplexer, a second optical multiplexer, a second wavelength division multiplexing coupler, and a second optical amplifier, a first control unit that controls the first light-emitting element, and a second control unit that controls the second light-emitting element. The first optical demultiplexer branches light output from the first light-emitting element and supplies the branched light to the first optical multiplexer and the second optical multiplexer, respectively, and the second optical demultiplexer branches light output from the second light-emitting element and supplies the branched light to the first optical multiplexer and the second optical multiplexer, respectively. The first optical multiplexer multiplexes the light supplied from the first optical demultiplexer and the second optical demultiplexer and supplies the multiplexed light to the first wavelength division multiplexing coupler, the second optical multiplexer multiplexes the light supplied from the first optical demultiplexer and the second optical demultiplexer and supplies the multiplexed light to the second wavelength division multiplexing coupler, the first wavelength division multiplexing coupler multiplexes the light multiplexed by the first optical multiplexer with a first optical signal and supplies the multiplexed light to the first optical amplifier, and the second wavelength division multiplexing coupler multiplexes the light multiplexed by the second optical multiplexer with a second optical signal and supplies the multiplexed light to the second optical amplifier.

[0010] An optical repeater according to the present disclosure includes a first control unit and a second control unit, and further includes a first unit and a second unit, each unit including a first light-emitting element, a second light-emitting element, and a third light-emitting element, a first optical demultiplexer, a second optical demultiplexer, a third optical demultiplexer, a first optical multiplexer / demultiplexer, a second optical multiplexer / demultiplexer, a third optical multiplexer / demultiplexer, a fourth optical multiplexer / demultiplexer, a fifth optical multiplexer / demultiplexer, and a sixth optical multiplexer / demultiplexer, respectively. The first control unit controls the first light-emitting element, the second light-emitting element, and the third light-emitting element of the first unit, and the second control unit controls the first light-emitting element, the second light-emitting element, and the third light-emitting element of the second unit. The first optical demultiplexer branches the light output from the first light-emitting element and supplies the branched light to the first optical multiplexer / demultiplexer of the first unit and the second unit, respectively; the second optical demultiplexer branches the light output from the second light-emitting element and supplies the branched light to the second optical multiplexer / demultiplexer of the first unit and the second unit, respectively; and the third optical demultiplexer branches the light output from the third light-emitting element and supplies the branched light to the third optical multiplexer / demultiplexer of the first unit and the second unit, respectively.the first optical multiplexer / demultiplexer of the first unit multiplexes and branches the light supplied from the first optical demultiplexer, and supplies the branched light to the fourth optical multiplexer / demultiplexer and the fifth optical multiplexer / demultiplexer of the first unit, respectively; the first optical multiplexer / demultiplexer of the second unit multiplexes and branches the light supplied from the first optical demultiplexer, and supplies the branched light to the fourth optical multiplexer / demultiplexer and the fifth optical multiplexer / demultiplexer of the second unit, respectively; the second optical multiplexer / demultiplexer of the first unit multiplexes and branches the light supplied from the second optical demultiplexer, and supplies the branched light to the fourth optical multiplexer / demultiplexer of the first unit and the second unit, respectively; The second optical multiplexer / demultiplexer of the second unit multiplexes and branches the light supplied from the second optical demultiplexer, and supplies the branched light to the sixth optical multiplexer / demultiplexer of the first unit and the second unit, respectively; the third optical multiplexer / demultiplexer of the first unit multiplexes and branches the light supplied from the third optical demultiplexer, and supplies the branched light to the fifth optical multiplexer / demultiplexer and the sixth optical multiplexer / demultiplexer of the first unit, respectively; and the third optical multiplexer / demultiplexer of the second unit multiplexes and branches the light supplied from the third optical demultiplexer, and supplies the branched light to the fifth optical multiplexer / demultiplexer and the sixth optical multiplexer / demultiplexer of the second unit, respectively. [Effects of the Invention]

[0011] The present disclosure makes it possible to provide an optical repeater that reduces power consumption and maintains robustness against failures in the control unit. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a configuration diagram of an optical repeater according to a first embodiment. [Figure 2] FIG. 2 is a diagram showing a part of the optical repeater surrounded by a dashed line in FIG. [Figure 3] FIG. 10 is a configuration diagram of an optical communication system according to a second embodiment. [Figure 4] FIG. 10 is a configuration diagram of an optical repeater according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] <First Embodiment> DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. Fig. 1 shows the configuration of an optical repeater according to the present embodiment. The optical repeater 100 according to this embodiment includes a control unit A101, a control unit B102, eight light-emitting elements (LDA1, LDA2, LDA3, LDA4, LDB1, LDB2, LDB3, LDB4), eight optical demultiplexers (CA11, CB11, CA12, CB12, CA13, CB13, CA14, CB14) that demultiplex the light output from the light-emitting elements, eight optical multiplexers (CA21, CB21, CA22, CB22, CA23, CB23, CA24, CB24) that multiplex the demultiplexed light, eight wavelength division multiplexing couplers (CA31, CB31, CA32, CB32, CA33, CB33, CA34, CB34) that multiplex the input optical signal SIG and the multiplexed light, and eight optical amplifiers (FA) that amplify the optical signal SIG.

[0014] The control unit A101 controls the light-emitting elements LDA1, LDA2, LDA3, and LDA4. The control unit B102 controls the remaining light-emitting elements LDB1, LDB2, LDB3, and LDB4 that are not controlled by the control unit A101.

[0015] Here, one light-emitting element, one optical demultiplexer, one optical multiplexer, one wavelength division multiplexing coupler, and one optical amplifier are considered to be one unit. In other words, the control unit A101 and the control unit B102 each control the light-emitting elements of four units.

[0016] Fig. 2 shows a portion of the optical repeater 100 enclosed by the dashed line in Fig. 1, i.e., the two units described above. Hereinafter, the unit equipped with the light-emitting element controlled by the control unit A101 will be referred to as the first unit, and the unit equipped with the light-emitting element controlled by the control unit B102 will be referred to as the second unit.

[0017] The amplification operation of the optical signal SIG in the optical repeater 100 will be described with reference to Figure 2. The optical demultiplexer CA11 of the first unit branches the light A1 output from the light emitting element LDA1. The branched light is supplied to the optical multiplexer CA21 of the first unit and the optical multiplexer CB21 of the second unit, respectively. At this time, the optical intensities supplied to the optical multiplexers CA21 and CB21 are each 50% of the light A1.

[0018] The optical demultiplexer CB11 of the second unit branches the light B1 output from the light emitting element LDB1. The branched light is supplied to the optical multiplexer CA21 of the first unit and the optical multiplexer CB21 of the second unit, respectively. At this time, the optical intensities supplied to the optical multiplexers CA21 and CB21 are each 50% of the light B1.

[0019] The optical demultiplexer according to this embodiment preferably uses a 1x2 optical fiber coupler. Although the light output from the light-emitting element shown in Fig. 2 is split into light with a 50% optical intensity by the optical demultiplexer, the split ratio of the light is not limited to this, and light split at any ratio may be supplied to the optical multiplexer.

[0020] The optical multiplexer CA21 of the first unit multiplexes light having 50% of the optical intensity of light A1 supplied from the optical demultiplexer CA11 with light having 50% of the optical intensity of light B1 supplied from the optical demultiplexer CB11, and supplies the combined pump light to the wavelength division multiplexing coupler CA31.

[0021] The optical multiplexer CB21 of the second unit multiplexes light having 50% of the optical intensity of light A1 supplied from the optical demultiplexer CA11 with light having 50% of the optical intensity of light B1 supplied from the optical demultiplexer CB11, and supplies the combined pump light to the wavelength division multiplexing coupler CB31.

[0022] The optical multiplexer according to this embodiment preferably uses a 1x2 optical fiber coupler.

[0023] The wavelength division multiplexing coupler CA31 multiplexes the input first optical signal SIG1 with the pumping light supplied from the optical multiplexer CA21 and supplies the multiplexed light to the first optical amplifier FA1. The wavelength division multiplexing coupler CB31 multiplexes the input first optical signal SIG2 with the pumping light supplied from the optical multiplexer CB21 and supplies the multiplexed light to the second optical amplifier FA2.

[0024] The first optical amplifier FA1 amplifies the first optical signal SIG1 using the light multiplexed by the wavelength division multiplexing coupler CA31, and the second optical amplifier FA2 amplifies the second optical signal SIG2 using the light multiplexed by the wavelength division multiplexing coupler CB31.

[0025] The optical amplifier according to this embodiment is preferably an erbium doped fiber amplifier (EDFA).

[0026] The control unit A101 and the control unit B102 control the four first units and the four second units, respectively, as described above. Therefore, the optical repeater according to the present disclosure controls the excitation light source having four light-emitting elements with one control unit, thereby reducing the number of control units and making it possible to suppress the power consumption of the optical repeater.

[0027] Furthermore, even if one of the control units A101 and B102 fails, the optical signals SIG1 and SIG2 can be amplified by the pump light controlled by the other control unit. Even if one of the light-emitting element LDA1 and light-emitting element LDB1 fails rather than the control unit, pump light with an intensity that is 50% of the light output from the light-emitting element can be supplied, so the function of the optical amplifier is maintained. Therefore, the optical repeater according to the present disclosure can maintain robustness against failures of the control unit and the pump light source.

[0028] In this way, the present disclosure can provide an optical repeater that reduces power consumption and maintains robustness against failures in the control unit and the excitation light source.

[0029] In addition, in this embodiment, a configuration has been described in which one control unit controls an excitation light source having four light-emitting elements, but the number of light-emitting elements provided in the excitation light source is not limited to four and may be five or more.

[0030] <Embodiment 2> In this embodiment, an optical communication system including an optical repeater according to embodiment 1 will be described. Fig. 3 shows the configuration of the optical communication system according to this embodiment.

[0031] The optical communication system according to the present embodiment includes an optical transmitter 201, an optical receiver 202, an optical fiber 203, and the optical repeater 100 according to the first embodiment. The optical transmitter 201 transmits an optical signal SIG, and the optical receiver 202 receives the optical signal SIG transmitted from the optical transmitter 201. The optical signal SIG is transmitted via the optical fiber 203.

[0032] In an optical communication system for long-distance transmission, such as a submarine optical cable system, the longer the distance the optical signal SIG is transmitted, the more significant the attenuation of the optical signal SIG becomes. Therefore, multiple optical repeaters 100 are inserted between an optical transmitter 201 and an optical receiver 202 to amplify the optical signal SIG.

[0033] The optical repeater 100 according to this embodiment has the same configuration as the optical repeater 100 according to the first embodiment. This makes it possible to provide an optical communication system including an optical repeater that reduces power consumption and maintains robustness against failures in the control unit and the excitation light source.

[0034] <Third Embodiment> In this embodiment, an optical repeater having a different configuration from the optical repeater according to the first embodiment will be described. Fig. 4 shows the configuration of the optical repeater according to this embodiment. The optical repeater 100 according to this embodiment includes a control unit A101, a control unit B102, six light-emitting elements (LDA1, LDA2, LDA3, LDB1, LDB2, LDB3), six optical demultiplexers (CA11, CB11, CA12, CB12, CA13, CB13) that demultiplex light output from the light-emitting elements, twelve optical multiplexers / demultiplexers (CA21, CB21, CA22, CB22, CA23, CB23, CA31, CB31, CA32, CB32, CA33, CB33) that multiplex the demultiplexed light and further demultiplex it, twelve wavelength division multiplexing couplers (WDMCPLs) that multiplex input optical signals SIG and multiplexed light, and twelve optical amplifiers (FAs) that amplify the optical signals SIG.

[0035] The control unit A101 controls the light emitting elements LDA1, LDA2, and LDA3. The control unit B102 controls the remaining light emitting elements LDB1, LDB2, and LDB3 that are not controlled by the control unit A101.

[0036] Here, three light-emitting elements, three optical demultiplexers, six optical multiplexers / demultiplexers, six wavelength division multiplexing couplers, and six optical amplifiers are regarded as one unit.

[0037] Hereinafter, a unit including light-emitting elements LDA1, LDA2, and LDA3 controlled by control unit A101 will be referred to as the first unit, and a unit including light-emitting elements LDB1, LDB2, and LDB3 controlled by control unit B102 will be referred to as the second unit.

[0038] The operations and functions of the light emitting element, optical demultiplexer, wavelength division multiplexing coupler, and optical amplifier according to this embodiment are the same as those of the first and second embodiments, and therefore, the description thereof may be omitted.

[0039] The six optical multiplexers / demultiplexers are provided in three each in the front and rear stages. Optical multiplexer / demultiplexer CA21, optical multiplexer / demultiplexer CA22, and optical multiplexer / demultiplexer CA23 of the first unit, and optical multiplexer / demultiplexer CB21, optical multiplexer / demultiplexer CB22, and optical multiplexer / demultiplexer CB23 of the second unit, are provided in the front stage. Optical multiplexer / demultiplexer CA31, optical multiplexer / demultiplexer CA32, and optical multiplexer / demultiplexer CA33 of the first unit, and optical multiplexer / demultiplexer CB31, optical multiplexer / demultiplexer CB32, and optical multiplexer / demultiplexer CB33 of the second unit, are provided in the rear stage.

[0040] The optical demultiplexer CA11 branches the light output from the light-emitting element LDA1. The branched light is supplied to the optical multiplexer / demultiplexer CA21 and the optical multiplexer / demultiplexer CB21. The optical demultiplexer CB11 branches the light output from the light-emitting element LDB1. The branched light is supplied to the optical multiplexer / demultiplexer CA21 and the optical multiplexer / demultiplexer CB21.

[0041] The optical demultiplexer CA12 branches the light output from the light-emitting element LDA2. The branched light is supplied to the optical multiplexer / demultiplexer CA22 and the optical multiplexer / demultiplexer CB22. The optical demultiplexer CB12 branches the light output from the light-emitting element LDB2. The branched light is supplied to the optical multiplexer / demultiplexer CA22 and the optical multiplexer / demultiplexer CB22.

[0042] The optical demultiplexer CA13 branches the light output from the light-emitting element LDA3. The branched light is supplied to the optical multiplexer / demultiplexer CA23 and the optical multiplexer / demultiplexer CB23. The optical demultiplexer CB13 branches the light output from the light-emitting element LDB3. The branched light is supplied to the optical multiplexer / demultiplexer CA23 and the optical multiplexer / demultiplexer CB23.

[0043] The optical multiplexer / demultiplexer CA21 multiplexes and branches the light supplied from the optical demultiplexer CA11 and the optical demultiplexer CB11. The branched light is supplied to the optical multiplexer / demultiplexer CA31 and the optical multiplexer / demultiplexer CA32, respectively.

[0044] The optical multiplexer / demultiplexer CB21 multiplexes and branches the light supplied from the optical demultiplexer CA11 and the optical demultiplexer CB11. The branched light is supplied to the optical multiplexer / demultiplexer CB31 and the optical multiplexer / demultiplexer CB32, respectively.

[0045] The optical multiplexer / demultiplexer CA22 multiplexes and branches the light supplied from the optical demultiplexer CA12 and the optical demultiplexer CB12. The branched light is supplied to the optical multiplexer / demultiplexer CA31 and the optical multiplexer / demultiplexer CB31, respectively.

[0046] The optical multiplexer / demultiplexer CB22 multiplexes and branches the light supplied from the optical demultiplexer CA12 and the optical demultiplexer CB12. The branched light is supplied to the optical multiplexer / demultiplexer CA33 and the optical multiplexer / demultiplexer CB33, respectively.

[0047] The optical multiplexer / demultiplexer CA23 multiplexes and branches the light supplied from the optical demultiplexer CA13 and the optical demultiplexer CB13. The branched light is supplied to the optical multiplexer / demultiplexer CA32 and the optical multiplexer / demultiplexer CA33, respectively.

[0048] The optical multiplexer / demultiplexer CB23 multiplexes and branches the light supplied from the optical demultiplexer CA13 and the optical demultiplexer CB13. The branched light is supplied to the optical multiplexer / demultiplexer CB32 and the optical multiplexer / demultiplexer CB33, respectively.

[0049] The optical multiplexer / demultiplexer according to this embodiment preferably uses a 2x2 optical fiber coupler.

[0050] The optical multiplexer / demultiplexer CA31, optical multiplexer / demultiplexer CB31, optical multiplexer / demultiplexer CA32, optical multiplexer / demultiplexer CB32, optical multiplexer / demultiplexer CA33, and optical multiplexer / demultiplexer CB33 multiplex and further branch the supplied light. The branched pump light is respectively supplied to wavelength division multiplexing couplers.

[0051] The wavelength division multiplexing coupler combines the input optical signal with the pumping light combined by optical multiplexer / demultiplexer CA31, optical multiplexer / demultiplexer CB31, optical multiplexer / demultiplexer CA32, optical multiplexer / demultiplexer CB32, optical multiplexer / demultiplexer CA33, and optical multiplexer / demultiplexer CB33, and supplies the combined light to the optical amplifiers. The optical amplifiers amplify the optical signals using the light combined by the wavelength division multiplexing coupler.

[0052] In this way, the present disclosure can provide an optical repeater that reduces power consumption and maintains robustness against failures in the control unit and the excitation light source.

[0053] The present disclosure is not limited to the above-described embodiments, and may be modified as appropriate without departing from the spirit and scope of the present disclosure. In addition, the present disclosure may be implemented by appropriately combining the respective embodiments.

[0054] A part or all of the above-described embodiments can be described as, but not limited to, the following supplementary notes. (Appendix 1) a first unit including a first light-emitting element, a first optical demultiplexer, a first optical multiplexer, a first wavelength division multiplexing coupler, and a first optical amplifier; a second unit including a second light-emitting element, a second optical demultiplexer, a second optical multiplexer, a second wavelength division multiplexing coupler, and a second optical amplifier; a first control unit that controls the first light-emitting element; a second control unit that controls the second light-emitting element, the first optical demultiplexer branches the light output from the first light-emitting element and supplies the branched lights to the first optical multiplexer and the second optical multiplexer, respectively; the second optical demultiplexer branches the light output from the second light-emitting element and supplies the branched lights to the first optical multiplexer and the second optical multiplexer, respectively; the first optical multiplexer multiplexes the light beams supplied from the first optical demultiplexer and the second optical demultiplexer, and supplies the multiplexed light beam to the first wavelength division multiplexing coupler; the second optical multiplexer multiplexes the light beams supplied from the first optical demultiplexer and the second optical demultiplexer, and supplies the multiplexed light beam to the second wavelength division multiplexing coupler; the first wavelength division multiplexing coupler multiplexes the light multiplexed by the first optical multiplexer with a first optical signal and supplies the multiplexed light to the first optical amplifier; the second wavelength division multiplexing coupler multiplexes the light multiplexed by the second optical multiplexer with a second optical signal, and supplies the multiplexed light to the second optical amplifier; Optical repeater. (Appendix 2) At least four first units are provided, and the first control unit controls the four first light-emitting elements; At least four second units are provided, and the second control unit controls four of the second light-emitting elements. 1. An optical repeater as defined in claim 1. (Appendix 3) the first optical amplifier and the second optical amplifier comprise erbium-doped optical fiber amplifiers; 3. An optical repeater according to claim 1 or 2. (Appendix 4) the first optical demultiplexer, the first optical multiplexer, the second optical demultiplexer, and the second optical multiplexer each comprise a 1x2 optical fiber coupler; 4. An optical repeater according to any one of claims 1 to 3. (Appendix 5) an optical transmitter for transmitting an optical signal; an optical receiver for receiving the optical signal; an optical fiber for transmitting the optical signal; an optical repeater inserted into the optical fiber, The optical repeater comprises: a first unit including a first light-emitting element, a first optical demultiplexer, a first optical multiplexer, a first wavelength division multiplexing coupler, and a first optical amplifier; a second unit including a second light-emitting element, a second optical demultiplexer, a second optical multiplexer, a second wavelength division multiplexing coupler, and a second optical amplifier; a first control unit that controls the first light-emitting element; a second control unit that controls the second light-emitting element, the first optical demultiplexer branches the light output from the first light-emitting element and supplies the branched lights to the first optical multiplexer and the second optical multiplexer, respectively; the second optical demultiplexer branches the light output from the second light-emitting element and supplies the branched lights to the first optical multiplexer and the second optical multiplexer, respectively; the first optical multiplexer multiplexes the light beams supplied from the first optical demultiplexer and the second optical demultiplexer, and supplies the multiplexed light beam to the first wavelength division multiplexing coupler; the second optical multiplexer multiplexes the light beams supplied from the first optical demultiplexer and the second optical demultiplexer, and supplies the multiplexed light beam to the second wavelength division multiplexing coupler; the first wavelength division multiplexing coupler multiplexes the light multiplexed by the first optical multiplexer with a first optical signal and supplies the multiplexed light to the first optical amplifier; the second wavelength division multiplexing coupler multiplexes the light multiplexed by the second optical multiplexer with a second optical signal, and supplies the multiplexed light to the second optical amplifier; Optical communication system. (Appendix 6) At least four first units are provided, and the first control unit controls the four first light-emitting elements; At least four second units are provided, and the second control unit controls four of the second light-emitting elements. 6. The optical communication system of claim 5. (Appendix 7) A first control unit; A second control unit; a first unit and a second unit respectively including a first light-emitting element, a second light-emitting element, and a third light-emitting element, a first optical demultiplexer, a second optical demultiplexer, and a third optical demultiplexer, a first optical multiplexer / demultiplexer, a second optical multiplexer / demultiplexer, a third optical multiplexer / demultiplexer, a fourth optical multiplexer / demultiplexer, a fifth optical multiplexer / demultiplexer, and a sixth optical multiplexer / demultiplexer; the first control unit controls the first light-emitting element, the second light-emitting element, and the third light-emitting element of the first unit; the second control unit controls the first light-emitting element, the second light-emitting element, and the third light-emitting element of the second unit; the first optical demultiplexer branches the light output from the first light-emitting element and supplies the branched light to the first optical multiplexer / demultiplexer of the first unit and the first optical multiplexer / demultiplexer of the second unit, respectively; the second optical demultiplexer branches the light output from the second light-emitting element and supplies the branched light to the second optical multiplexer / demultiplexer of the first unit and the second unit, respectively; the third optical demultiplexer branches the light output from the third light-emitting element and supplies the branched light to the third optical multiplexer / demultiplexer of the first unit and the third optical demultiplexer of the second unit, respectively; the first optical multiplexer / demultiplexer of the first unit multiplexes and branches the light supplied from the first optical demultiplexer, and supplies the branched light to the fourth optical multiplexer / demultiplexer and the fifth optical multiplexer / demultiplexer of the first unit, respectively; the first optical multiplexer / demultiplexer of the second unit multiplexes and branches the light supplied from the first optical demultiplexer, and supplies the branched light to the fourth optical multiplexer / demultiplexer and the fifth optical multiplexer / demultiplexer of the second unit, respectively; the second optical multiplexer / demultiplexer of the first unit multiplexes and branches the light supplied from the second optical demultiplexer, and supplies the branched light to the fourth optical multiplexer / demultiplexer of the first unit and the fourth optical demultiplexer of the second unit, respectively; the second optical multiplexer / demultiplexer of the second unit multiplexes and branches the light supplied from the second optical demultiplexer, and supplies the branched light to the sixth optical multiplexer / demultiplexer of the first unit and the sixth optical demultiplexer of the second unit, respectively; the third optical multiplexer / demultiplexer of the first unit multiplexes and branches the light supplied from the third optical demultiplexer, and supplies the branched light to the fifth optical multiplexer / demultiplexer and the sixth optical multiplexer / demultiplexer of the first unit, respectively; the third optical multiplexer / demultiplexer of the second unit multiplexes and branches the light supplied from the third optical demultiplexer, and supplies the branched light to the fifth optical multiplexer / demultiplexer and the sixth optical multiplexer / demultiplexer of the second unit, respectively; Optical repeater. (Appendix 8) the first unit and the second unit each include six wavelength division multiplexing couplers and six optical amplifiers; the fourth optical multiplexer / demultiplexer, the fifth optical multiplexer / demultiplexer, and the sixth optical multiplexer / demultiplexer multiplex and branch the light supplied from the first optical demultiplexer, the second optical demultiplexer, and the third optical demultiplexer, respectively, and supply the branched light to the six wavelength division multiplexing couplers, respectively; the six wavelength division multiplexing couplers respectively combine the light combined by the fourth optical multiplexer / demultiplexer, the fifth optical multiplexer / demultiplexer, and the sixth optical multiplexer / demultiplexer with an optical signal, and supply the combined light to the six optical amplifiers, respectively; 8. An optical repeater as defined in claim 7. [Explanation of symbols]

[0055] 100 Optical repeater 101 Control Unit A 102 Control Unit B 201 Optical transmitter 202 Optical receiver 203 Optical Fiber

Claims

1. a first unit including a first light-emitting element, a first optical demultiplexer, a first optical multiplexer, a first wavelength division multiplexing coupler, and a first optical amplifier; a second unit including a second light-emitting element, a second optical demultiplexer, a second optical multiplexer, a second wavelength division multiplexing coupler, and a second optical amplifier; a first control unit that controls the first light-emitting element; a second control unit that controls the second light-emitting element, the first optical demultiplexer branches the light output from the first light-emitting element and supplies the branched lights to the first optical multiplexer and the second optical multiplexer, respectively; the second optical demultiplexer branches the light output from the second light-emitting element and supplies the branched lights to the first optical multiplexer and the second optical multiplexer, respectively; the first optical multiplexer multiplexes the light beams supplied from the first optical demultiplexer and the second optical demultiplexer, and supplies the multiplexed light beam to the first wavelength division multiplexing coupler; the second optical multiplexer multiplexes the light beams supplied from the first optical demultiplexer and the second optical demultiplexer, and supplies the multiplexed light beam to the second wavelength division multiplexing coupler; the first wavelength division multiplexing coupler multiplexes the light multiplexed by the first optical multiplexer with a first optical signal and supplies the multiplexed light to the first optical amplifier; the second wavelength division multiplexing coupler multiplexes the light multiplexed by the second optical multiplexer with a second optical signal and supplies the multiplexed light to the second optical amplifier; At least four of the first units are provided, and the first control unit controls the four first light-emitting elements; At least four second units are provided, and the second control unit controls four of the second light-emitting elements. Optical repeater.

2. the first optical amplifier and the second optical amplifier comprise erbium-doped optical fiber amplifiers; 2. The optical repeater according to claim 1.

3. the first optical demultiplexer, the first optical multiplexer, the second optical demultiplexer, and the second optical multiplexer each include a 1x2 optical fiber coupler; 3. The optical repeater according to claim 1 or 2.

4. an optical transmitter for transmitting an optical signal; an optical receiver for receiving the optical signal; an optical fiber for transmitting the optical signal; an optical repeater inserted into the optical fiber, The optical repeater comprises: a first unit including a first light-emitting element, a first optical demultiplexer, a first optical multiplexer, a first wavelength division multiplexing coupler, and a first optical amplifier; a second unit including a second light-emitting element, a second optical demultiplexer, a second optical multiplexer, a second wavelength division multiplexing coupler, and a second optical amplifier; a first control unit that controls the first light-emitting element; a second control unit that controls the second light-emitting element, the first optical demultiplexer branches the light output from the first light-emitting element and supplies the branched lights to the first optical multiplexer and the second optical multiplexer, respectively; the second optical demultiplexer branches the light output from the second light-emitting element and supplies the branched lights to the first optical multiplexer and the second optical multiplexer, respectively; the first optical multiplexer multiplexes the light beams supplied from the first optical demultiplexer and the second optical demultiplexer, and supplies the multiplexed light beam to the first wavelength division multiplexing coupler; the second optical multiplexer multiplexes the light beams supplied from the first optical demultiplexer and the second optical demultiplexer, and supplies the multiplexed light beam to the second wavelength division multiplexing coupler; the first wavelength division multiplexing coupler multiplexes the light multiplexed by the first optical multiplexer with a first optical signal and supplies the multiplexed light to the first optical amplifier; the second wavelength division multiplexing coupler multiplexes the light multiplexed by the second optical multiplexer with a second optical signal and supplies the multiplexed light to the second optical amplifier; At least four of the first units are provided, and the first control unit controls the four first light-emitting elements; At least four second units are provided, and the second control unit controls four of the second light-emitting elements. Optical communication system.

5. the first optical amplifier and the second optical amplifier comprise erbium-doped optical fiber amplifiers; 5. The optical communication system according to claim 4.

6. the first optical demultiplexer, the first optical multiplexer, the second optical demultiplexer, and the second optical multiplexer each include a 1x2 optical fiber coupler; 6. An optical communication system according to claim 4 or 5.

7. A first control unit; A second control unit; a first unit and a second unit respectively including a first light-emitting element, a second light-emitting element, and a third light-emitting element; a first optical demultiplexer, a second optical demultiplexer, and a third optical demultiplexer; and a first optical multiplexer / demultiplexer, a second optical multiplexer / demultiplexer, a third optical multiplexer / demultiplexer, a fourth optical multiplexer / demultiplexer, a fifth optical multiplexer / demultiplexer, and a sixth optical multiplexer / demultiplexer; the first control unit controls the first light-emitting element, the second light-emitting element, and the third light-emitting element of the first unit; the second control unit controls the first light-emitting element, the second light-emitting element, and the third light-emitting element of the second unit; the first optical demultiplexers of the first unit and the second unit respectively branch the light output from the first light-emitting elements of the first unit and the second unit, and supply the branched light to the first optical multiplexers and demultiplexers of the first unit and the second unit, the second optical demultiplexers of the first unit and the second unit respectively branch the light output from the second light-emitting elements of the first unit and the second unit, and supply the branched light to the second optical multiplexers and demultiplexers of the first unit and the second unit, the third optical demultiplexers of the first unit and the second unit respectively branch the light output from the third light-emitting elements of the first unit and the second unit, and supply the branched light to the third optical multiplexers and demultiplexers of the first unit and the second unit, the first optical multiplexer / demultiplexer of the first unit multiplexes and branches the light supplied from the first optical demultiplexers of the first unit and the second unit, and supplies the branched light to the fourth optical multiplexer / demultiplexer and the fifth optical multiplexer / demultiplexer of the first unit, respectively; the first optical multiplexer / demultiplexer of the second unit multiplexes and branches the light supplied from the first optical demultiplexers of the first unit and the second unit, and supplies the branched light to the fourth optical multiplexer / demultiplexer and the fifth optical multiplexer / demultiplexer of the second unit, respectively; the second optical multiplexer / demultiplexer of the first unit multiplexes and branches the light supplied from the second optical demultiplexers of the first unit and the second unit, and supplies the branched light to the fourth optical multiplexer / demultiplexer of the first unit and the second unit, respectively; the second optical multiplexer / demultiplexer of the second unit multiplexes and branches the light supplied from the second optical demultiplexers of the first unit and the second unit, and supplies the branched light to the sixth optical multiplexer / demultiplexer of the first unit and the second unit, respectively; the third optical multiplexer / demultiplexer of the first unit multiplexes and branches the light supplied from the third optical demultiplexers of the first unit and the second unit, and supplies the branched light to the fifth optical multiplexer / demultiplexer and the sixth optical multiplexer / demultiplexer of the first unit, respectively; the third optical multiplexer / demultiplexer of the second unit multiplexes and branches the light supplied from the third optical demultiplexers of the first unit and the second unit, and supplies the branched light to the fifth optical multiplexer / demultiplexer and the sixth optical multiplexer / demultiplexer of the second unit, respectively; Optical repeater.

8. each of the first unit and the second unit includes six wavelength division multiplexing couplers and six optical amplifiers; the fourth optical multiplexer / demultiplexer, the fifth optical multiplexer / demultiplexer, and the sixth optical multiplexer / demultiplexer of the first unit and the second unit multiplex and branch the light supplied from the first optical multiplexer / demultiplexer, the second optical multiplexer / demultiplexer, and the third optical multiplexer / demultiplexer of the first unit and the second unit, respectively, and supply the branched light to the six wavelength division multiplexing couplers of the first unit and the second unit, respectively; the six wavelength division multiplexing couplers of the first unit and the second unit respectively combine the light combined by the fourth optical multiplexer / demultiplexer, the fifth optical multiplexer / demultiplexer, and the sixth optical multiplexer / demultiplexer with an optical signal, and supply the combined light to the six optical amplifiers of the first unit and the second unit, respectively.

8. The optical repeater according to claim 7.

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