分布式拉曼测温系统中APD盖革模式控制

The controlling of InGaAs avalanche photodiode with Geiger mode in Raman distributed temperature sensing system

研究分布式拉曼光纤测温系统中雪崩光电二极管(avalanche photo diode,APD)于盖革模式的增益特性,以实现对微弱后向拉曼散射光的探测与响应。设计了APD的温度偏压控制系统,确保其可以长期稳定地工作于盖革模式。实验研究了APD暗电流和偏置电压,以及外界温度对其增益的影响。结果表明,可以通过调节APD的偏置电压和工作温度,使其达到最大增益,即工作在盖革模式。利用STM32单片机,设计了APD温度偏压控制系统,通过精密控制温度变化,同步改变APD两端偏压的变化,进而可将APD准确控制于盖革模式。

The gain characteristic of avalanche photodiode(APD) in Geiger mode in the distributed Raman optical fiber tempera- ture sensing is analyzed to realize the detection and response of the weak Raman backscattering. We also design a temperature and bias voltage of APD control system, ensuring that it can be operating in Geiger mode steadily in the long term, In the experi- ments, the influence of external temperature, voltage and dark current on the gain of the APD are investigated. It is shown that the amplified light current in the maximum gain can be got by control the converse voltage and the external temperature of APD. A system is designed to control the temperature and the bias voltage of APD using the microcontroller of STM32. The APD can be precisely worked in Geiger-Mode through adjusting the temperature and bias voltage synchronously.