OTDR设计中APD偏置电压的自适应精确控制

Adaptive precise control of APD bias voltage in OTDR design

针对相同偏置电压下雪崩光电二极管(APD)的增益会随温度变化,从而影响到光时域反射仪(OTDR)的动态范围的问题,提出了一种APD偏置电压自适应精确控制的方案。在各个适宜的工作温度下,该方案可以保证偏置电压始终工作在接近雪崩电压,使APD在最佳增益时稳定工作,从而提高OTDR的动态指标,并解决OTDR高低温测试时动态范围波动大的问题,使得动态范围波动被控制在0.3 d B以内。

Aiming at the problem that the avalanche photo diode(APD) gain changes with temperature under the same voltage,which affects the dynamic range of the optical time domain reflectometer(OTDR), an adaptive precise control scheme of APD bias voltage is proposed. At each suitable operating temperature, This scheme can ensure that the bias voltage is always close to the avalanche voltage, and make APD work stably at the best gain, so as to improve the dynamic index of OTDR, and solve the problem of large dynamic range fluctuation in the high and low temperature test of OTDR, so that the dynamic range fluctuation is controlled within 0.3 dB.