| 摘要 |
PURPOSE:To devise an optical signal receiver to be automatically started and set in the standby state synchronously with detection/-nondetection of a signal light in the optical signal receiver demodulating a signal light through the use of a coherent local light source. CONSTITUTION:The optical signal receiver is set in the standby state while extinguishing a local light source 12, and a bias current change in light receiving elements 5, 6 is converted into a voltage change at the arrival of a signal light and the result is used for a start signal for cold starting. A cold start control circuit 11 receiving the start signal lights a local light source to start the receiver automatically. After the receiver is started, an intermediate frequency signal is being detected from a signal light, and when the signal is not detected, the state restores again to the standby state. Thus, the detection for a signal light for cold starting is realized by addition of a simple circuit. |
