Raman amplifier

摘要

Raman amplification pumping light output from a pumping light source unit (13) is supplied to a Raman amplification optical fiber (11) through an optical circulator (122). The remaining Raman amplification pumping light is detected by a light-receiving element (16) through an optical circulator (121) and bandpass filter (15). Signal light that has reached a Raman amplifier (1) propagates through the Raman amplification optical fiber (11) while being Raman-amplified. A control section (14) controls the power or spectral shape of Raman amplification pumping light output from each of N pumping light sources included in the pumping light source unit (13) on the basis of the power of the remaining Raman amplification pumping light, which is detected by the light-receiving element (16). Hence, a Raman amplifier capable of easily controlling gain spectrum flattening in the signal light wavelength band can be obtained.