| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical amplifier having a simple constitution, in which deterioration in optical S/N ratio for one wavelength band is decreased and which copes with restrictions on a mounting space and consuming power, etc., in the optical amplifier that amplifies optical signals in two wavelength bands. SOLUTION: This optical amplifier is provided with a C/L band optical amplifying part 5 that amplifies each optical signal in a C band and an L band, a branching filter 1, that branches an output light from the C/L-band optical amplifying part 5 into the C band and the L band, an L-band optical amplifying part 3 that amplifies the optical signal in the L band branched by the branching filter 1, and a wave synthesizer 4 that combines optical signal in the C band branched by the branching filter 1 and the optical signal in the L band amplified by the L-band optical amplifying part 3. A part of excitation light in a 1,480 nm band used in the C/L-band optical amplifying part 5 is supplied to a Raman- amplifying/generating medium of a transmission channel L via an input terminal IN, and the Raman-amplified optical signal in the L band is inputted to the C/L-band optical amplifying part 5. |
