通过调节负载提高RoF系统中大电流光探测器的饱和特性

Improvement of saturation characteristics of high-photocurrent photodiode for RoF system through load adjustment

为提高射频光纤通信系统(ROF)中大电流光探测器(PD)的饱和特性,基于等效电路模型,对大电流工作下负载电阻大小对PD饱和特性的影响进行了理论分析,并利用微波负载牵引自动测量系统对PD负载电阻加以调节。通过实验测试了不同负载电阻下PD电压摆幅的变化及其对于探测器饱和特性、响应带宽的影响。理论和测试结果均表明,降低负载电阻可有效提高PD饱和电流和响应带宽。因此,根据应用条件适当降低负载电阻可改善PD的性能。

The loading effect on high-photocurrent photodiode is studied based on equivalent circuit mod- el. Fast and precise tuning of the load of photodiode is realized with the automated load-pull system,and the voltage swing changes due to variation in load impedance and their influence on saturation current and response bandwidth are investigated. Both the theoretical and experimental results show that the saturation current and bandwidth of a photodiode can be improved by reducing its load. It can be expected that the enhanced photodiode performance can be obtained by adopting the reduced load resistance according to application requirements.