An optical repeater comprising: three or more light sources (S1, S2, S3) configured to output lights; three or more optical amplification units (A1, A2, A3) configured to amplify optical signals (SIG1, SIG2, SIG3) using input excitation lights (L4, L5, L6); and an optical distribution unit configured to branch the light output from each of the three or more light sources (S1, S2, S3) into two branched lights (L11, L12, L21, L22, L31, L32) and distribute the branched lights (L11, L12, L21, L22, L31, L32) in such a manner that each of the three or more optical amplification units (A1, A2, A3) receives the branched lights (L11, L12, L21, L22, L31, L32) branched from the lights from two different light sources (S1, S2, S3) as the excitation light (L4, L5, L6), wherein the optical repeater is characterized in that the optical distribution unit comprises: three or more demultiplexers (D1, D2, D3) configured to receive the lights output from the three or more light sources (S1, S2, S3), respectively, and branch the received lights into the two branched lights (L11, L12, L21, L22, L31, L32); and three or more multiplexers (M1, M2, M3) configured to receive the branched lights (L11, L12, L21, L22, L31, L32) output from two different demultiplexers (D1, D2, D3), and output the excitation lights (L4, L5, L6) obtained by multiplexing the received lights to any one of the three or more optical amplification units (A1, A2, A3), respectively. three or more light sources (S1, S2, S3) configured to output lights; three or more optical amplification units (A1, A2, A3) configured to amplify optical signals (SIG1, SIG2, SIG3) using input excitation lights (L4, L5, L6); and an optical distribution unit configured to branch the light output from each of the three or more light sources (S1, S2, S3) into two branched lights (L11, L12, L21, L22, L31, L32) and distribute the branched lights (L11, L12, L21, L22, L31, L32) in such a manner that each of the three or more optical amplification units (A1, A2, A3) receives the branched lights (L11, L12, L21, L22, L31, L32) branched from the lights from two different light sources (S1, S2, S3) as the excitation light (L4, L5, L6), wherein the optical repeater is characterized in that the optical distribution unit comprises: three or more demultiplexers (D1, D2, D3) configured to receive the lights output from the three or more light sources (S1, S2, S3), respectively, and branch the received lights into the two branched lights (L11, L12, L21, L22, L31, L32); and three or more multiplexers (M1, M2, M3) configured to receive the branched lights (L11, L12, L21, L22, L31, L32) output from two different demultiplexers (D1, D2, D3), and output the excitation lights (L4, L5, L6) obtained by multiplexing the received lights to any one of the three or more optical amplification units (A1, A2, A3), respectively. three or more demultiplexers (D1, D2, D3) configured to receive the lights output from the three or more light sources (S1, S2, S3), respectively, and branch the received lights into the two branched lights (L11, L12, L21, L22, L31, L32); and three or more multiplexers (M1, M2, M3) configured to receive the branched lights (L11, L12, L21, L22, L31, L32) output from two different demultiplexers (D1, D2, D3), and output the excitation lights (L4, L5, L6) obtained by multiplexing the received lights to any one of the three or more optical amplification units (A1, A2, A3), respectively. <EOS>