The invention discloses a circuit for protecting an APD
receiver. The circuit comprises the APD
receiver, wherein the bias input end of the APD
receiver is grounded through a first
decoupling capacitor and a second
decoupling capacitor, the bias input end of the APD receiver is connected with a first output end of a
mirror image circuit, the input end of the
mirror image circuit is connected with the output end of a boost
control circuit, and the input end of the boost
control circuit is connected with a
microprocessor; the second output end of the
mirror image circuit is grounded through a first
resistor and meanwhile connected to the
microprocessor; the
microprocessor is connected with a
signal losing LOS end of a
limiting amplifier which is connected with a trans-impedance
amplifier (TIA), the TIA is connected with the output end of the APD receiver, a second
resistor is connected between the bias input end of the APD receiver and the first output end of the mirror image circuit, and the resistance value of the second
resistor ranges from 10 K
ohm to 100 K
ohm. Through the circuit, an APD can be effectively protected against damage, the risk that a module loses
efficacy is reduced, and the service life of the
optical module is prolonged.