| 摘要 |
PROBLEM TO BE SOLVED: To suppress the optical output decrease and noise figure increase, without increasing the exciting light power by dividing an optical amplification medium, providing a wavelength demultiplexer for separating or demultiplexing an exciting light and signal light and feeding the exciting light directly to the next stage and signal light to the next stage via an optical signal characteristic compensator. SOLUTION: The optical amplifier A01 comprises an optical amplification medium composed of rate earth doped optical fibers 1a, 1b and demultiplexers. A signal light is incident via an optical isolator 4a and wavelength demultiplexer 2 on the fiber 1a, amplified with an exciting light incident via the demultiplexer 2 on this fiber 1a, then incident via a wavelength demultiplexer 3, optical signal characteristic compensator 6 and again demultiplexer 3 on the optical fiber 1b and again amplified with the exciting light incident on this fiber 1b via only the multiplexer 3. Thus it is possible to compensate the loss of the compenstator 6 and suppress the noise figure increase, without increasing he exciting light power. |
