| 摘要 |
<P>PROBLEM TO BE SOLVED: To protect an APD (Avalanche Photo Diode) module from excessive input of an optical signal. <P>SOLUTION: A circuit is provided with: a bias voltage application unit 3 which applies a bias voltage to the APD module 1; an APD current monitor unit 4 which outputs a monitor current according to an APD current generated by the APD module 1; and a bias voltage control unit 5 which controls the bias voltage according to the monitor current output from the APD current monitor unit 4. <P>COPYRIGHT: (C)2011,JPO&INPIT |
