| 摘要 |
PROBLEM TO BE SOLVED: To provide a Raman amplifier in which the width of gain spectrum of Raman amplification is enlarged at a low cost and an optical communication system. SOLUTION: In a Raman amplifier 10, Raman amplification stimulating light beams outputted from a stimulating light source 14 are divided into two branches, i.e., one branch is supplied to a first Raman amplification optical fiber 111 through a first multiplexer/demultiplexer 121 and the other branch is supplied to a second Raman amplification optical fiber 112 through a second multiplexer/demultiplexer 122. Signal light beams inputted to an input end 10a are Raman amplified, propagated through the fiber 111, go through the multiplexer/demultiplexer 121 and an optical isolator 13, Raman amplified, propagated through the fiber 112, go through he multiplexer/demultiplexer 122 and outputted from an output end 10b. The two fibers 111 and 112 have mutually different composition in the optical waveguide region and are serially connected. |
