RAMAN AMPLIFIER

摘要

PROBLEM TO BE SOLVED: To provide a Raman amplifier which facilitates control over gain spectrum flattening in the wavelength band of signal light. SOLUTION: Exciting light for Raman amplification which is outputted from an exciting light source unit 13 is supplied to an optical fiber 11 for Raman amplification via an optical circulator 122. The remaining exciting light for Raman amplification is detected by a photodetecting element 16 via an optical circulator 121 and a band-pass filter 15. The signal light reaching the Raman amplifier 1 is propagated in the optical fiber 11 for Raman amplification and processed by Raman amplification. A control part 14 controls the power or the shape of the spectrum of the exciting light for Raman amplification outputted from N exciting light sources included in the exciting light source unit according to the power of the remaining exciting light for Raman amplification detected by the photodetecting element 16.