| 摘要 |
PURPOSE:To take out a constant output when the input level of signal light is within the amplification range of an optical fiber amplifier. CONSTITUTION:A light source 1A outputs excitation light of a wavelength lambdab and a multiplexer 2A multiplexes the excitation light of a wavelength lambdab with signal light of a wavelength lambdaa. An optical fiber amplifier 3 amplifies the signal light of a wavelength lambdaa using the excitation light of a wavelength lambdab being included in an output of the multiplexer 2A as an energy source and an optical filter 4 makes the signal light of a wavelength lambdaa pass through and intercepts the excitation light of a wavelength lambdab. A photodetector 5 converts the signal light of a wavelength lambdaa into an electrical signal and an amplifier 6 amplifies an output of the photodetector 5. A detector 8 detects the magnitude of an output of the amplifier 6 and a control circuit 9 controls an output of the excitation light from the light source 1A to control an input of the detector 8 in a prescribed magnitude. |
