Optical repeater and optical communication system

Abstract

To provide an optical repeater and an optical communication system, capable of suppressing a voltage consumption in the case of having an odd number of light sources.SOLUTION: An optical repeater according to a present disclosure, comprises n units of an odd number of at least three or more. Each of the n units comprises: an excitation light source; a first optical branching filter; a second optical branching filter; a first optical multiplexer; and a second optical multiplexer, respectively. The first optical branching filter branches an excitation light from the excitation light source into 1:n-1. The second optical branching filter branches an excitation light of which a ratio in branching by the first optical branching filter is n-1 into the excitation light of n-1. In addition, the second optical branching filter outputs the excitation light obtained by being branched to each first optical multiplexer belonging to n-1 units that are other than a unit to which the second optical branching filter belongs. The first optical multiplexer multiplexes the excitation light to be input into a single excitation light and outputs it to the second optical multiplexer. The second optical multiplexer multiplexes the excitation light of which the radio obtained by being branched by the first optical branching filter is 1 and the single excitation light obtained by being multiplexed by the first optical multiplexer.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] In optical communication systems aimed at long-distance transmission, such as undersea optical cable systems, a plurality of optical repeaters are inserted in the transmission path to electrically compensate for attenuation of optical signals.

[0003] Patent Document 1 discloses that in an optical repeater equipped with a plurality of pump light sources, unequal branching couplers are used to multiplex and demultiplex pump light. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2018 / 097074 Summary of the Invention [Problem to be solved by the invention]

[0005] In an optical communication system, the effect of voltage drop in optical repeaters increases as the number of optical repeaters inserted increases, so there is a demand for suppressing voltage drop inside optical repeaters.

[0006] In order to ensure the voltage drop and reliability of the optical repeater, Patent Document 1 discloses that a plurality of pumping lights are multiplexed and demultiplexed in an optical repeater having a plurality of pumping light sources, and pumped by a plurality of optical amplifiers.

[0007] However, the above-mentioned method is not preferable because when an optical repeater has an odd number of pumping light sources, it becomes necessary to terminate some of the optical amplifiers, and the power of the pumping light used for the terminated optical amplifiers is wasted.

[0008] In view of the above, an object of the present disclosure is to provide an optical repeater and an optical communication system that reduce voltage consumption when an odd number of optical fiber components are provided. [Means for solving the problem]

[0009] The optical repeater according to the present disclosure includes n units, the n units being an odd number of at least 3 or more, and the n units include a pumping light source, a first optical demultiplexer, a second optical demultiplexer, a first optical multiplexer, and a second optical multiplexer, and the first optical demultiplexer demultiplexes pumping light from the pumping light source at a ratio of 1:n-1, the second optical demultiplexer demultiplexes the pumping light with a ratio of n-1 demultiplexed by the first optical demultiplexer into n-1 pumping lights, and the second optical demultiplexer is a multiplexer that ... The first optical multiplexer outputs the split pump light to each of the first optical multiplexers belonging to the n-1 units other than the unit to which the first optical multiplexer belongs, and the first optical multiplexer combines the pump light input from each of the optical demultiplexers belonging to the n-1 units other than the unit to which the first optical multiplexer belongs into a single pump light and outputs the single pump light to the second optical multiplexer, and the second optical multiplexer combines the pump light split by the first optical demultiplexer at a ratio of 1 with the single pump light combined by the first optical multiplexer.

[0010] The optical repeater of the present disclosure comprises n units, where n is an odd number of at least 3 or more, and each of the n units comprises an excitation light source, an optical splitter, and an optical multiplexer, and the optical splitter splits excitation light from the excitation light source into n excitation lights, and the optical splitter outputs the n excitation lights to the optical multiplexers of the n units, respectively, and the optical multiplexer combines the excitation light input from the optical splitters of the n units into a single excitation light.

[0011] The optical repeater according to the present disclosure includes a first unit including a first excitation light source, a first optical splitter, a second optical splitter, a first optical multiplexer, and a second optical multiplexer; a second unit including a second excitation light source, a third optical splitter, a fourth optical splitter, a third optical multiplexer, and a fourth optical multiplexer; and a third unit including a third excitation light source, a fifth optical splitter, a sixth optical splitter, a fifth optical multiplexer, and a sixth optical multiplexer. The first optical splitter splits the excitation light output from the first excitation light source. the third optical demultiplexer demultiplexes the pumping light output by the second pumping light source at a ratio of 1 to a third pumping light at a ratio of 1 to a fourth pumping light at a ratio of 2; the fifth optical demultiplexer demultiplexes the pumping light output by the third pumping light source at a ratio of 1 to a fifth pumping light at a ratio of 1 to a sixth pumping light at a ratio of 2; the second optical demultiplexer demultiplexes the pumping light output by the second pumping light source at a ratio of 1 to a fifth pumping light at a ratio of 1 to a sixth pumping light at a ratio of 2; the fourth optical demultiplexer demultiplexes the fourth pumping light 1:1 into a second 1 pumping light and a second 2 pumping light, the fourth optical demultiplexer demultiplexes the fourth pumping light 1:1 into a fourth 1 pumping light and a fourth 2 pumping light, the sixth optical demultiplexer demultiplexes the sixth pumping light 1:1 into a sixth 1 pumping light and a sixth 2 pumping light, the first optical multiplexer multiplexes the fourth 1 pumping light and the sixth 1 pumping light into a seventh pumping light, and the third optical multiplexer The second optical multiplexer multiplexes the second 1 pumping light and the sixth 2 pumping light to generate an eighth pumping light, the fifth optical multiplexer multiplexes the second 2 pumping light and the fourth 2 pumping light to generate a ninth pumping light, the second optical multiplexer multiplexes the first pumping light and the seventh pumping light, the fourth optical multiplexer multiplexes the second pumping light and the eighth pumping light, and the sixth optical multiplexer multiplexes the third pumping light and the ninth pumping light.

[0012] An optical repeater according to the present disclosure includes a first unit including a first pumping light source, a first optical splitter, and a first optical multiplexer, a second unit including a second pumping light source, a second optical splitter, and a second optical multiplexer, and a third unit including a third pumping light source, a third optical splitter, and a third optical multiplexer, wherein the first optical splitter splits the pumping light output from the first pumping light source into three, resulting in a first pumping light, a second pumping light, and a third pumping light, and the second optical splitter splits the pumping light output from the second pumping light source into three, the third optical splitter splits the pumping light output by the third pumping light source into three, into seventh, eighth, and ninth pumping light; the first optical multiplexer multiplexes the first pumping light, the fourth pumping light, and the seventh pumping light; the second optical multiplexer multiplexes the second pumping light, the fifth pumping light, and the eighth pumping light; and the third optical multiplexer multiplexes the third pumping light, the sixth pumping light, and the ninth pumping light.

[0013] In addition, 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 the above-mentioned optical repeater that is inserted into the optical fiber. Effect of the Invention

[0014] The present disclosure makes it possible to provide an optical repeater and an optical communication system that reduce voltage consumption when an odd number of optical fiber components are provided. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a configuration diagram of an optical repeater according to the present disclosure. [Diagram 2] 1A to 1C are diagrams illustrating the operation of an optical repeater according to the present disclosure. [Diagram 3] 1 is a configuration diagram of an optical communication system according to the present disclosure. [Figure 4] FIG. 1 is a configuration diagram of an optical repeater according to the present disclosure. [Diagram 5] FIG. 1 is a configuration diagram of an optical repeater according to the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] <Embodiment 1> Hereinafter, the present disclosure will be described with reference to the drawings. Fig. 1 shows the configuration of an optical repeater according to the present disclosure. The optical repeater 100 includes n pump light sources, where n is an odd number. In Fig. 1, in order to facilitate understanding of the present disclosure, a case where n=3 will be described.

[0017] The optical repeater 100 includes three pumping light sources, three first optical demultiplexers, three second optical demultiplexers, three first optical multiplexers, and three second optical multiplexers. In Fig. 1, the pumping light sources are described as LD1, LD2, and LD3, the first optical demultiplexers as C11, C21, and C31, the second optical demultiplexers as C12, C22, and C32, the first optical multiplexers as C13, C23, and C33, and the second optical multiplexers as C14, C24, and C34, respectively.

[0018] Furthermore, the optical repeater 100 includes three wavelength division multiplexing couplers and three optical amplifiers. In Fig. 1, the wavelength division multiplexing couplers are indicated as WDMC1, WDMC2, and WDMC3, and the optical amplifiers are indicated as EDFA1, EDFA2, and EDFA3, respectively.

[0019] Here, a part of the optical repeater 100 surrounded by a dashed line in Fig. 1, i.e., one pumping light source, one first optical demultiplexer, one second optical demultiplexer, one first optical multiplexer, one second optical multiplexer, one wavelength division multiplexing coupler, and one optical amplifier, is regarded as one unit. In other words, the optical repeater 100 includes three units, a first unit, a second unit, and a third unit.

[0020] Here, the operation of amplifying an optical signal in the optical repeater 100 will be described with reference to Fig. 2. Fig. 2 focuses on the first unit of the optical repeater 100.

[0021] The pumping light source LD1 outputs pumping light L1. The first optical demultiplexer C11 demultiplexes the output pumping light L1 at a ratio of 1:2 into pumping light L1(1 / 3) having a ratio of 1, i.e., a light intensity that is 1 / 3 of the pumping light L1, and pumping light L1(2 / 3) having a ratio of 2, i.e., a light intensity that is 2 / 3 of the pumping light L1.

[0022] 2, the operations of the second and third units are the same as those of the first unit. Therefore, the first optical multiplexer C21 of the second unit demultiplexes the pumping light L2 output from the pumping light source LD2 into pumping light L2(1 / 3) having a ratio of 1 and pumping light L2(2 / 3) having a ratio of 2. Also, the first optical multiplexer C31 of the third unit demultiplexes the pumping light L3 output from the pumping light source LD3 into pumping light L3(1 / 3) having a ratio of 1 and pumping light L3(2 / 3) having a ratio of 2.

[0023] The second optical demultiplexer C12 demultiplexes the pumping light L1 (2 / 3) output from the first optical demultiplexer C11 at a ratio of 2, at 1:1, to two pumping lights L1 (1 / 3). Next, the second optical demultiplexer C12 outputs the two demultiplexed pumping lights L1 (1 / 3) to the first optical multiplexer C23 of the second unit and the first optical multiplexer C33 of the third unit, respectively. In other words, the second optical demultiplexer C12 of the first unit outputs the demultiplexed pumping lights to units (second unit and third unit) other than the unit (first unit) to which the second optical demultiplexer C12 belongs, respectively.

[0024] Similarly, the second optical demultiplexer C22 of the second unit demultiplexes the pumping light L2(2 / 3) output from the first optical demultiplexer C22 at a ratio of 2 to two pumping lights L2(1 / 3) at a ratio of 1:1. Next, the second optical demultiplexer C22 of the second unit outputs the two demultiplexed pumping lights L2(1 / 3) to the first optical multiplexer C13 of the first unit and the first optical multiplexer C33 of the third unit, respectively.

[0025] Furthermore, the second optical demultiplexer C32 of the third unit demultiplexes the pumping light L3 (2 / 3) output from the first optical demultiplexer C32 at a ratio of 2 to two pumping lights L3 (1 / 3) at a ratio of 1:1. Next, the second optical demultiplexer C32 of the third unit outputs the two demultiplexed pumping lights L3 (1 / 3) to the first optical multiplexer C13 of the first unit and the first optical multiplexer C23 of the second unit, respectively.

[0026] The first optical multiplexer C13 of the first unit multiplexes the pumping light L2 (1 / 3) output from the second optical demultiplexer C22 of the second unit and the pumping light L3 (1 / 3) output from the second optical demultiplexer C32 of the third unit. In other words, the first optical multiplexer C13 of the first unit multiplexes the pumping light output from units (the second unit and the third unit) other than the unit (the first unit) to which the first optical multiplexer C13 belongs, into a single pumping light.

[0027] Similarly, the first optical multiplexer C23 of the second unit multiplexes the pumping light L1 (1 / 3) output from the second optical demultiplexer C12 of the first unit and the pumping light L3 (1 / 3) output from the second optical demultiplexer C32 of the third unit into a single pumping light. Also, the first optical multiplexer C33 of the third unit multiplexes the pumping light L1 (1 / 3) output from the second optical demultiplexer C12 of the first unit and the pumping light L2 (1 / 3) output from the second optical demultiplexer C22 of the second unit into a single pumping light.

[0028] The second optical multiplexer C14 of the first unit multiplexes the pumping light L1 (1 / 3) having a ratio of 1 output from the first optical demultiplexer C11 with the single pumping light output from the first optical multiplexer C13. Similarly, the second optical multiplexer C24 of the second unit multiplexes the pumping light L2 (1 / 3) having a ratio of 1 output from the first optical demultiplexer C21 with the single pumping light output from the first optical multiplexer C23. Also, the second optical multiplexer C34 of the third unit multiplexes the pumping light L3 (1 / 3) having a ratio of 1 output from the first optical demultiplexer C31 with the single pumping light output from the first optical multiplexer C33.

[0029] The first optical demultiplexer, the second optical demultiplexer, the first optical multiplexer, and the second optical multiplexer according to this embodiment preferably use 1x2 optical fiber couplers, and when n is an odd number greater than 3, the first optical demultiplexer and the second optical multiplexer preferably use 1x2 optical fiber couplers, and the second optical demultiplexer and the first optical multiplexer preferably use 1x(n-1) optical fiber couplers.

[0030] The wavelength division multiplexing coupler WDMC1 of the first unit multiplexes the optical signal SIG1 input to the first unit with the pumping light multiplexed by the second optical multiplexer C14, and outputs the multiplexed pumping light to the optical amplifier EDFA1. The optical amplifier EDFA1 of the first unit amplifies the optical signal SIG1 using the pumping light multiplexed by the wavelength division multiplexing coupler WDMC1.

[0031] Similarly, the wavelength division multiplexing coupler WDMC2 of the second unit multiplexes the optical signal SIG2 input to the second unit with the pumping light multiplexed by the second optical multiplexer C24, and outputs the multiplexed pumping light to the optical amplifier EDFA2. The optical amplifier EDFA2 of the second unit amplifies the optical signal SIG2 using the pumping light multiplexed by the wavelength division multiplexing coupler WDMC2.

[0032] Moreover, the wavelength division multiplexing coupler WDMC3 of the third unit multiplexes the optical signal SIG3 input to the third unit with the pumping light multiplexed by the second optical multiplexer C34, and outputs the multiplexed pumping light to the optical amplifier EDFA3. The optical amplifier EDFA3 of the third unit amplifies the optical signal SIG3 using the pumping light multiplexed by the wavelength division multiplexing coupler WDMC3.

[0033] The optical amplifier according to this embodiment is preferably an erbium doped fiber amplifier (EDFA).

[0034] In this way, the optical repeater according to the present disclosure does not need to terminate some of the optical amplifiers even when the optical repeater has an odd number of pumping light sources, so the power of the pumping light is not wasted and it is possible to suppress the voltage consumption. Furthermore, the optical repeater according to the present disclosure can supply pumping light even if some of the pumping light sources LD1, LD2, and LD3 fail, so it is possible to maintain the amplification of the signal light while ensuring redundancy. <Embodiment 2>

[0035] Next, an optical communication system including an optical repeater according to the present disclosure will be described. Fig. 3 shows the configuration of the optical communication system according to the present disclosure. The optical communication system 200 includes an optical transmitter 201, an optical receiver 202, an optical fiber 203, and the optical repeater 100 described in 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.

[0036] In an optical communication system for long-distance transmission such as an undersea 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, a plurality of optical repeaters 100 are inserted between an optical transmitter 201 and an optical receiver 202 to amplify the optical signal SIG.

[0037] The optical repeater 100 according to the present embodiment has a configuration similar to that of the optical repeater 100 described in the embodiment 1. With such a configuration, even if the optical repeater has an odd number of light sources, it is possible to provide an optical communication system that suppresses voltage consumption and ensures redundancy. <Embodiment 3>

[0038] Next, 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 an optical repeater according to the present disclosure. The optical repeater 100 has n pump light sources, where n is an odd number. In Fig. 4, the case where n=3 will be described in order to facilitate understanding of the present disclosure.

[0039] The optical repeater 100 includes three pumping light sources, three optical demultiplexers, and three optical multiplexers. In Fig. 4, the pumping light sources are indicated as LD1, LD2, and LD3, the optical demultiplexers are indicated as C11, C21, and C31, and the optical multiplexers are indicated as C12, C22, and C32.

[0040] Furthermore, the optical repeater 100 includes three wavelength division multiplexing couplers and three optical amplifiers. In Fig. 4, the wavelength division multiplexing couplers are indicated as WDMC1, WDMC2, and WDMC3, and the optical amplifiers are indicated as EDFA1, EDFA2, and EDFA3, respectively.

[0041] As in the first embodiment, a part of the optical repeater 100 surrounded by a dashed line in Fig. 4, i.e., one pumping light source, one optical demultiplexer, one optical multiplexer, one wavelength division multiplexing coupler, and one optical amplifier, is regarded as one unit. In other words, the optical repeater 100 includes three units, a first unit, a second unit, and a third unit.

[0042] The pumping light source LD1 outputs pumping light. The optical splitter C11 splits the output pumping light into three, and outputs the split pumping light to the optical multiplexers C12, C22, and C32 of each unit. The operations of the second and third units are the same as those of the first unit. Therefore, the optical multiplexer C21 of the second unit splits the pumping light output from the pumping light source LD2 into three, and outputs the split pumping light to the optical multiplexers C12, C22, and C32 of each unit. The optical multiplexer C31 of the third unit splits the pumping light output from the pumping light source LD3 into three, and outputs the split pumping light to the optical multiplexers C12, C22, and C32 of each unit.

[0043] The optical multiplexer C12 in the first unit multiplexes the pumping light input from the optical demultiplexers C11, C21, and C31 of each unit into a single pumping light, and outputs it to the wavelength division multiplexing coupler WDMC1. Similarly, the optical multiplexer C22 in the second unit multiplexes the pumping light input from the optical demultiplexers C11, C21, and C31 of each unit into a single pumping light, and outputs it to the wavelength division multiplexing coupler WDMC2. Moreover, the optical multiplexer C32 in the third unit multiplexes the pumping light input from the optical demultiplexers C11, C21, and C31 of each unit into a single pumping light, and outputs it to the wavelength division multiplexing coupler WDMC3.

[0044] The optical demultiplexer and optical multiplexer according to the present embodiment preferably use 1x3 optical fiber couplers, and when n is an odd number greater than 3, the optical demultiplexer and optical multiplexer according to the present embodiment preferably use 1xn optical fiber couplers.

[0045] The wavelength division multiplexing coupler WDMC1 of the first unit combines the optical signal SIG1 input to the first unit with the pumping light combined by the optical combiner C12, and outputs the combined pumping light to the optical amplifier EDFA1. The optical amplifier EDFA1 of the first unit amplifies the optical signal SIG1 using the pumping light combined by the wavelength division multiplexing coupler WDMC1.

[0046] Similarly, the wavelength division multiplexing coupler WDMC2 of the second unit multiplexes the optical signal SIG2 input to the second unit with the pumping light multiplexed by the optical multiplexer C22, and outputs the multiplexed pumping light to the optical amplifier EDFA2. The optical amplifier EDFA2 of the second unit amplifies the optical signal SIG2 using the pumping light multiplexed by the wavelength division multiplexing coupler WDMC2.

[0047] Moreover, the wavelength division multiplexing coupler WDMC3 of the third unit multiplexes the optical signal SIG3 input to the third unit with the pumping light multiplexed by the optical multiplexer C32, and outputs the multiplexed pumping light to the optical amplifier EDFA3. The optical amplifier EDFA3 of the third unit amplifies the optical signal SIG3 using the pumping light multiplexed by the wavelength division multiplexing coupler WDMC3.

[0048] The optical amplifier according to this embodiment is preferably an erbium doped fiber amplifier (EDFA).

[0049] In this way, the optical repeater according to the present disclosure does not need to terminate some of the optical amplifiers even when the optical repeater has an odd number of pumping light sources, so the power of the pumping light is not wasted and it is possible to suppress the voltage consumption. Furthermore, the optical repeater according to the present disclosure can supply pumping light even if some of the pumping light sources LD1, LD2, and LD3 fail, so it is possible to maintain the amplification of the signal light while ensuring redundancy.

[0050] Fig. 5 shows the configuration of an optical repeater according to the present disclosure when n = 5. The optical repeater 100 includes five pumping light sources, five optical demultiplexers, and five optical multiplexers. In Fig. 5, pumping light sources: LD1, LD2, LD3, LD4, LD5, optical demultiplexers: C11, C21, C31, C41, C51, and optical multiplexers: C12, C22, C32, C42, C52 are described, respectively.

[0051] Furthermore, the optical repeater 100 includes five wavelength division multiplexing couplers and five optical amplifiers. In Fig. 5, the wavelength division multiplexing couplers are indicated as WDMC1, WDMC2, WDMC3, WDMC4, and WDMC5, and the optical amplifiers are indicated as EDFA1, EDFA2, EDFA3, EDFA4, and EDFA5, respectively.

[0052] As in the first embodiment, a part of the optical repeater 100 surrounded by a dashed line in Fig. 5, i.e., one pumping light source, one optical demultiplexer, one optical multiplexer, one wavelength division multiplexing coupler, and one optical amplifier, is regarded as one unit. In other words, the optical repeater 100 includes five units, namely, a first unit, a second unit, a third unit, a fourth unit, and a fifth unit.

[0053] The pumping light source LD1 outputs pumping light. The optical splitter C11 splits the output pumping light into five, and outputs the split pumping light to the optical multiplexers C12, C22, C32, C42, and C52 of each unit. The operations of the second to fifth units are the same as those of the first unit.

[0054] The optical multiplexer C12 of the first unit multiplexes the pumping light input from the optical demultiplexers C11, C21, C31, C41, and C51 of each unit into a single pumping light, and outputs it to the wavelength division multiplexing coupler WDMC1. Note that the operations of the second to fifth units are the same as those of the first unit.

[0055] The optical demultiplexer and optical multiplexer according to this embodiment preferably use a 1x5 optical fiber coupler.

[0056] The wavelength division multiplexing coupler WDMC1 of the first unit multiplexes the optical signal SIG1 input to the first unit with the pumping light multiplexed by the optical multiplexer C12, and outputs the multiplexed pumping light to the optical amplifier EDFA1. The optical amplifier EDFA1 of the first unit amplifies the optical signal SIG1 using the pumping light multiplexed by the wavelength division multiplexing coupler WDMC1. The operations of the second to fifth units are the same as that of the first unit.

[0057] In this way, the optical repeater according to the present disclosure does not need to terminate some of the optical amplifiers even when the optical repeater has an odd number of pumping light sources, so the power of the pumping light is not wasted and it is possible to suppress the voltage consumption. Furthermore, the optical repeater according to the present disclosure can supply pumping light even if some of the pumping light sources LD1 to LD5 fail, so it is possible to maintain the amplification of the signal light while ensuring redundancy.

[0058] Although the present disclosure has been described above with reference to the embodiments, the present disclosure is not limited to the above-mentioned embodiments. Various modifications that can be understood by a person skilled in the art can be made to the configuration and details of the present disclosure within the scope of the present disclosure. Furthermore, each embodiment can be appropriately combined with other embodiments.

[0059] A part or all of the above-described embodiments can be described as, but is not limited to, the following supplementary notes. (Appendix 1) The system has n units, n being an odd number of at least 3; Each of the n units includes a pumping light source, a first optical demultiplexer, a second optical demultiplexer, a first optical multiplexer, and a second optical multiplexer; the first optical demultiplexer demultiplexes the pumping light from the pumping light source in a ratio of 1:n-1; The second optical demultiplexer demultiplexes the pumping light having a demultiplexing ratio of n-1 by the first optical demultiplexer into n-1 pumping lights; Furthermore, the second optical demultiplexer outputs the demultiplexed pump light to each of the first optical multiplexers belonging to n-1 units other than the unit to which the second optical demultiplexer belongs; the first optical multiplexer multiplexes pump light input from each of the optical demultiplexers belonging to n-1 units other than the unit to which the first optical multiplexer belongs, into a single pump light, and outputs the single pump light to the second optical multiplexer; The second optical multiplexer multiplexes the pumping light having a ratio of 1 split by the first optical demultiplexer and the single pumping light multiplexed by the first optical multiplexer. Optical repeater. (Appendix 2) The n units further include a wavelength division multiplexing coupler that multiplexes the optical signal and the pumping light multiplexed by the second optical multiplexer; and an optical amplifier for inputting and amplifying the light multiplexed by the wavelength division multiplexing coupler. 2. An optical repeater as defined in claim 1. (Appendix 3) the first optical demultiplexer, the first optical multiplexer, the second optical demultiplexer, and the second optical multiplexer each include an optical fiber coupler; 3. An optical repeater according to claim 1 or 2. (Appendix 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; and an optical repeater according to any one of claims 1 to 3, which is inserted into the optical fiber. Optical communication system. (Appendix 5) The system has n units, n being an odd number of at least 3; Each of the n units includes an excitation light source, an optical demultiplexer, and an optical multiplexer; The optical splitter splits the pumping light from the pumping light source into n pumping lights, Furthermore, the optical demultiplexer outputs the n pumping lights to the optical multiplexers of the n units, respectively; The optical multiplexer multiplexes the pumping lights input from the optical demultiplexers of the n units into a single pumping light. Optical repeater. (Appendix 6) The n units further include a wavelength division multiplexing coupler that multiplexes the optical signal and the pumping light multiplexed by the optical multiplexer; and an optical amplifier for inputting and amplifying the light multiplexed by the wavelength division multiplexing coupler. 6. An optical repeater as defined in claim 5. (Appendix 7) each of the optical demultiplexer and the optical multiplexer includes an optical fiber coupler; 7. The optical repeater according to claim 5 or 6. (Appendix 8) an optical transmitter for transmitting an optical signal; an optical receiver for receiving the optical signal; an optical fiber for transmitting the optical signal; and an optical repeater according to any one of appendix 5 to 7, which is inserted into the optical fiber. Optical communication system. (Appendix 9) a first unit including a first pumping light source, a first optical demultiplexer, a second optical demultiplexer, a first optical multiplexer, and a second optical multiplexer; a second unit including a second pumping light source, a third optical demultiplexer, a fourth optical demultiplexer, a third optical multiplexer, and a fourth optical multiplexer; a third unit including a third pumping light source, a fifth optical demultiplexer, a sixth optical demultiplexer, a fifth optical multiplexer, and a sixth optical multiplexer; the first optical splitter splits the pumping light output from the first pumping light source at a ratio of 1:2 into a first pumping light having a ratio of 1 and a second pumping light having a ratio of 2; the third optical demultiplexer demultiplexes the pumping light output from the second pumping light source at a ratio of 1:2 into a third pumping light having a ratio of 1 and a fourth pumping light having a ratio of 2; the fifth optical demultiplexer demultiplexes the pumping light output from the third pumping light source at a ratio of 1:2 into a fifth pumping light having a ratio of 1 and a sixth pumping light having a ratio of 2; the second optical splitter splits the second pumping light at a ratio of 1:1 into a second 1 pumping light and a second 2 pumping light; the fourth optical demultiplexer demultiplexes the fourth pumping light at a ratio of 1:1 into a fourth 1 pumping light and a fourth 2 pumping light; the sixth optical demultiplexer demultiplexes the sixth pumping light at a ratio of 1:1 into sixth 1 pumping light and sixth 2 pumping light; the first optical multiplexer multiplexes the fourth pumping light and the sixth pumping light to generate a seventh pumping light; the third optical multiplexer multiplexes the second pumping light and the sixth pumping light to generate an eighth pumping light; the fifth optical multiplexer multiplexes the second pumping light and the fourth pumping light to generate a ninth pumping light; the second optical multiplexer multiplexes the first pumping light and the seventh pumping light; the fourth optical multiplexer multiplexes the second pumping light and the eighth pumping light; The sixth optical multiplexer multiplexes the third pumping light and the ninth pumping light. Optical repeater. (Appendix 10) the first unit further includes a first wavelength division multiplexing coupler that multiplexes a first optical signal and the pumping light multiplexed by the second optical multiplexer, and a first optical amplifier that inputs and amplifies the light multiplexed by the first wavelength division multiplexing coupler; the second unit further includes a second wavelength division multiplexing coupler that multiplexes a second optical signal and the pumping light multiplexed by the fourth optical multiplexer, and a second optical amplifier that inputs and amplifies the light multiplexed by the second wavelength division multiplexing coupler; The third unit further includes a third wavelength division multiplexing coupler that multiplexes a third optical signal and the pumping light multiplexed by the sixth optical multiplexer, and a third optical amplifier that inputs and amplifies the light multiplexed by the third wavelength division multiplexing coupler. 10. The optical repeater according to claim 9. (Appendix 11) the first optical demultiplexer, the second optical demultiplexer, the first optical multiplexer, the second optical multiplexer, the third optical demultiplexer, the fourth optical demultiplexer, the third optical multiplexer, the fourth optical multiplexer, the fifth optical demultiplexer, the sixth optical demultiplexer, the fifth optical multiplexer, and the sixth optical multiplexer each include an optical fiber coupler; 11. The optical repeater according to claim 9 or 10. (Appendix 12) an optical transmitter for transmitting an optical signal; an optical receiver for receiving the optical signal; an optical fiber for transmitting the optical signal; and an optical repeater according to any one of claims 9 to 11, which is inserted into the optical fiber. Optical communication system. (Appendix 13) a first unit including a first pumping light source, a first optical demultiplexer, and a first optical multiplexer; a second unit including a second pumping light source, a second optical demultiplexer, and a second optical multiplexer; a third unit including a third pumping light source, a third optical demultiplexer, and a third optical multiplexer; the first optical splitter splits the pumping light output from the first pumping light source into three, that is, a first pumping light, a second pumping light, and a third pumping light; the second optical splitter splits the pumping light output from the second pumping light source into three, that is, a fourth pumping light, a fifth pumping light, and a sixth pumping light; the third optical splitter splits the pumping light output from the third pumping light source into three, that is, seventh pumping light, eighth pumping light, and ninth pumping light; the first optical multiplexer multiplexes the first pumping light, the fourth pumping light, and the seventh pumping light; the second optical multiplexer multiplexes the second pumping light, the fifth pumping light, and the eighth pumping light; The third optical multiplexer multiplexes the third pumping light, the sixth pumping light, and the ninth pumping light. Optical repeater. (Appendix 14) the first unit further includes a first wavelength division multiplexing coupler that multiplexes a first optical signal and the pumping light multiplexed by the first optical multiplexer, and a first optical amplifier that inputs and amplifies the light multiplexed by the first wavelength division multiplexing coupler; the second unit further includes a second wavelength division multiplexing coupler that multiplexes a second optical signal and the pumping light multiplexed by the second optical multiplexer, and a second optical amplifier that inputs and amplifies the light multiplexed by the second wavelength division multiplexing coupler; The third unit further includes a third wavelength division multiplexing coupler that multiplexes a third optical signal and the pumping light multiplexed by the third optical multiplexer, and a third optical amplifier that inputs and amplifies the light multiplexed by the third wavelength division multiplexing coupler. 14. The optical repeater according to claim 13. (Appendix 15) the first optical demultiplexer, the first optical multiplexer, the second optical demultiplexer, the second optical multiplexer, the third optical demultiplexer, and the third optical multiplexer each include an optical fiber coupler; 15. The optical repeater according to claim 13 or 14. (Appendix 16) an optical transmitter for transmitting an optical signal; an optical receiver for receiving the optical signal; an optical fiber for transmitting the optical signal; and an optical repeater according to any one of claims 13 to 15, which is inserted into the optical fiber. Optical communication system. [Explanation of symbols]

[0060] 100 Optical repeater 200 Optical Communication Systems 201 Optical transmitter 202 Optical Receiver 203 Optical Fiber

Claims

1. The apparatus includes n units, the n units being an odd number of at least 3, each of the n units includes a pumping light source, a first optical demultiplexer, a second optical demultiplexer, a first optical multiplexer, and a second optical multiplexer; the first optical demultiplexer demultiplexes the pumping light from the pumping light source in a ratio of 1:n-1; The second optical demultiplexer demultiplexes the pumping light having a demultiplexing ratio of n-1 by the first optical demultiplexer into n-1 pumping lights, Furthermore, the second optical demultiplexer outputs the demultiplexed pump light to each of the first optical multiplexers belonging to n-1 units other than the unit to which the second optical demultiplexer belongs; the first optical multiplexer multiplexes pump light input from each of the optical demultiplexers belonging to n-1 units other than the unit to which the first optical multiplexer belongs, into a single pump light, and outputs the single pump light to the second optical multiplexer; The second optical multiplexer multiplexes the pumping light having a ratio of 1 split by the first optical demultiplexer and the single pumping light multiplexed by the first optical multiplexer. Optical repeater.

2. The n units further include a wavelength division multiplexing coupler that multiplexes the optical signal and the pumping light multiplexed by the second optical multiplexer; and an optical amplifier for inputting and amplifying the light multiplexed by the wavelength division multiplexing coupler.

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 an optical fiber coupler; 3. An 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; and the optical repeater according to claim 1 or 2, which is inserted into the optical fiber. Optical communication system.

5. The apparatus includes n units, the n units being an odd number of at least 3, Each of the n units includes an excitation light source, an optical demultiplexer, and an optical multiplexer; The optical splitter splits the pumping light from the pumping light source into n pumping lights, Further, the optical demultiplexer outputs the n pumping lights to the optical multiplexers of the n units, respectively; The optical multiplexer multiplexes the pumping lights input from the optical demultiplexers of the n units into a single pumping light. Optical repeater.

6. The n units further include a wavelength division multiplexing coupler that multiplexes the optical signal and the pumping light multiplexed by the optical multiplexer; and an optical amplifier for inputting and amplifying the light multiplexed by the wavelength division multiplexing coupler.

6. The optical repeater according to claim 5.

7. each of the optical demultiplexer and the optical multiplexer includes an optical fiber coupler; 7. An optical repeater according to claim 5 or 6.

8. an optical transmitter for transmitting an optical signal; an optical receiver for receiving the optical signal; an optical fiber for transmitting the optical signal; and an optical repeater according to claim 5 or 6, which is inserted into the optical fiber. Optical communication system.

9. a first unit including a first pumping light source, a first optical demultiplexer, a second optical demultiplexer, a first optical multiplexer, and a second optical multiplexer; a second unit including a second pumping light source, a third optical demultiplexer, a fourth optical demultiplexer, a third optical multiplexer, and a fourth optical multiplexer; a third unit including a third pumping light source, a fifth optical demultiplexer, a sixth optical demultiplexer, a fifth optical multiplexer, and a sixth optical multiplexer; the first optical splitter splits the pumping light output from the first pumping light source at a ratio of 1:2 into a first pumping light having a ratio of 1 and a second pumping light having a ratio of 2; the third optical demultiplexer demultiplexes the pumping light output from the second pumping light source at a ratio of 1:2 into a third pumping light having a ratio of 1 and a fourth pumping light having a ratio of 2; the fifth optical demultiplexer demultiplexes the pumping light output from the third pumping light source at a ratio of 1:2 into a fifth pumping light having a ratio of 1 and a sixth pumping light having a ratio of 2; the second optical splitter splits the second pumping light at a ratio of 1:1 into a second pumping light 1 and a second pumping light 2; the fourth optical splitter splits the fourth pumping light at a ratio of 1:1 into a fourth pumping light 1 and a fourth pumping light 2; the sixth optical demultiplexer demultiplexes the sixth pumping light at a ratio of 1:1 into sixth 1 pumping light and sixth 2 pumping light; the first optical multiplexer multiplexes the fourth 1st pumping light and the sixth 1st pumping light to generate a seventh pumping light; the third optical multiplexer multiplexes the second 1st pumping light and the sixth 2nd pumping light to generate an eighth pumping light; the fifth optical multiplexer multiplexes the second pumping light and the fourth pumping light to generate a ninth pumping light; the second optical multiplexer multiplexes the first pumping light and the seventh pumping light; the fourth optical multiplexer multiplexes the second pumping light and the eighth pumping light; The sixth optical multiplexer multiplexes the third pumping light and the ninth pumping light. Optical repeater.

10. a first unit including a first pumping light source, a first optical splitter, and a first optical multiplexer; a second unit including a second pumping light source, a second optical splitter, and a second optical multiplexer; a third unit including a third pumping light source, a third optical demultiplexer, and a third optical multiplexer; the first optical splitter splits the pumping light output from the first pumping light source into three, that is, a first pumping light, a second pumping light, and a third pumping light; the second optical splitter splits the pumping light output from the second pumping light source into three, that is, a fourth pumping light, a fifth pumping light, and a sixth pumping light; the third optical splitter splits the pumping light output from the third pumping light source into three, that is, seventh pumping light, eighth pumping light, and ninth pumping light; the first optical multiplexer multiplexes the first pumping light, the fourth pumping light, and the seventh pumping light; the second optical multiplexer multiplexes the second pumping light, the fifth pumping light, and the eighth pumping light; The third optical multiplexer multiplexes the third pumping light, the sixth pumping light, and the ninth pumping light. Optical repeater.

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