Circuit, optical module and method for protecting APD receiver

Abstract

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.

Description

technical field [0001] The invention relates to the field of optical transceiver modules, in particular to a circuit, an optical module and a method for protecting an APD receiver in the optical module. Background technique [0002] The receiving end circuit of the optical module currently using the APD receiver is as attached figure 1 As shown, the microprocessor MCU controls the boost control circuit to output a high-voltage signal. The high-voltage signal is divided into two bias paths with proportional current output through the mirror current source circuit. One output is supplied to the high-voltage pin of the APD receiver, and passes through C1 and C2 two decoupling capacitors filter, so that the APD receiver obtains enough voltage to avalanche, resulting in a multiplication effect. After the APD obtains enough voltage, it converts the optical signal into an electrical signal, and converts it into a differential signal through the transimpedance amplifier TIA and out...

AI Technical Summary

Problems solved by technology

[0003] In order to obtain the best sensitivity, the MCU will control the boost control circuit to control the bias voltage of the APD receiver near the avalanche point. At this time, the multiplication factor of the APD receiver is large, and a small light input can get a larger light output. Current, when the optical power input to the APD receiver is very large, the excessive photocurrent flowing through the APD receiver will cause damage to the APD receiver

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