千兆无源光网络上行光信号特性研究与检测方案

Characteristic Research and Detection Scheme of Gigabit Passive Optical Network Upstream Optical Signal

由于千兆无源光网络系统中的上行光信号采用高速突发模式,故对其特性的检测是实现实时光层监测的难点。详细分析了上行光信号的传输特性、帧开销及噪声模型。并在此基础上,设计了一种检测方案,该方案通过高阻抗的前置放大器将信号引出,不影响原系统的正常工作,从而满足了实时检测的需要;通过峰值检波电路将高频突发信号降为低频进行处理,大大降低了检测的难度;在求出信号的平均功率后,利用底层光接收机模块中自带的限幅放大与数字判决功能修正误差。由于该方案对输入信号的信噪比有较大提升,且利用了系统的数字判决功能获取信号的占空比信息,故其实现成本低廉,检测精度理想。实验仿真的结果证明了该方案的可行性。

It is difficult to realize real-time power detection as the upstream signal of gigabit passive optical network（GPON） system is high-speed burst mode.Based on the analysis of the upstream signal transmission characteristics,the frame overhead,and the noise model,a new detection method is presented.This method raises the signal to the original system with pre-through high-impedance amplifier,which does not affect the performance of the original system.High-frequency burst signal will be down converted for processing,through the peak detecting and low-pass filtering.A limiting amplifier and digital decision device of low-level optical receiver module can be used to correct the error after the signal′s average power is obtained.Since the method can improve the signal-to-noise ratio,and make full use of system function to obtain information of the duty ratio,it is low-cost and has high detection accuracy.The experimental result has shown that the method is quite suitable for GPON system upstream signal power detection.