| 摘要 |
PURPOSE:To prevent an optical receiver from causing a code error and ampli tude variation even if light is branched by an optical switch, by selecting the speed of changing the size of the control signal of the optical switch smaller than the gain adjusting speed of an automatic gain adjusting circuit in an optical receiver. CONSTITUTION:Five voltages Vl, Va, Vb, Vc and Vh are applied to the input terminal of an analog switch 101 with five-inputs and one-output, and any one of them shows up according to a control signal. The output of the analog switch 101 is inputted to an integration circuit 102 configured with a resistance 103 and a capacitor 104 through an electric wire 106. The output of the integration circuit 102 is impressed on the optical switch 304 through an electric wire 107. Thus a controlled voltage is impressed on the optical switch 304 through the integration circuit 102, whereby a sudden change in the branch ratio of the optical switch 304, a code error, amplification an fluctuation can be prevented.
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