| 摘要 |
PURPOSE:To offer the structure which varies passing wavelength following the variation in the wavelength of signal light as to the structure of the band- pass filter module which is inevitable when the optical amplifier of an optical communication system is constituted. CONSTITUTION:A band-pass filter(BPF) 1 is composed of a low-pass filter(LPF) 2 and a high-pass filter(HPF) 3. A monitor means 4 consisting of an LPF monitor 5 and an HPF monitor 6 monitors part of reflected light or transmitted light of the LPF 2 and HPF 3. A control mechanism 7 performs follow-up control according to the signal from the monitor means 4 so that the passing wavelength of the BPF 1 is equal to the wavelength lambdas of signal light at all times. |
