In order to implement dynamic bias voltage compensation for the thermal drift of APD gain

high precision A/D and D/A circuits are designed.Millivolt-grade bias voltage control precision and 0.2℃ sampling precision are attainable for APD.On the basis of the fiberoptic sensing system

the linear relationship between the bias voltage and temperature of APD gain and the bias voltage compensation formula for the thermal drift errors of the gain are acquired by using the data collection and processing technology when the APD gain is stable

so the sensing system can be used to make real-time compensation for the thermal drift of the gain with a precision high enough to satisfy the requirement of the system.