| 摘要 |
PROBLEM TO BE SOLVED: To regulate a simple gain profile. SOLUTION: In response to WDM signal light inputted from input port 10, a WDM optical coupler 12 outputs a first signal light applying a transmission characteristic of transmissivity increasing as the wavelength becomes longer from output port Y0, and outputs a second signal light applying a transmission characteristic of transmissivity increasing as the wavelength becomes shorter on the contrary from output port Y1. An optical selector 14 is connected to a selected contact point 14a in an initial state. An optical coupler 16 supplies most of the signal light from the optical selector 14 from output port Y0 to input port X0 of an optical coupler 18, and supplies the rest from output port Y1 to an optical power monitor circuit 20. The optical power monitor circuit 20 detects the optical power level of a plurality of signal wavelength components from the output light of port Y1 of the optical coupler 16, and notices it to a control circuit 28. The control circuit 28 calculates a gain profile from the output of the optical power monitor circuit 20, and controls the optical selector 14 so that the gain profile of the WDM signal light becomes flatter. |
