| 摘要 |
An optical amplifier circuit includes an optical amplifying unit for amplifying a light signal having a predetermined wavelength to output an amplified light signal, first and second optical branching units each for branching a part of the amplified light signal to output branched light signals, and a band rejection optical filter for removing light within a center wavelength band to allow only spontaneous emission light to be selectively transmitted. A subtractor outputs a control signal according to a difference between the light signal branched by the first optical branching unit and the spontaneous emission light. A controller controls the output of the amplified light signal based on the control signal, thereby to maintain precisely a constant light output level. |
