平衡探测法抑制RoF链路输出信号噪声的研究

Research on the Noise Suppression of RoF Link Output Signal by Balanced Detection Method

提出了一种通过相干平衡探测抑制ROF链路输出信号噪声的方法。此方法通过引入本振光与信号光进行耦合,输出光通过减法器抑制光信号的直流扰动进而抑制RIN,间接抑制输出信号噪声并提高输出信号的信噪比。通过optisystem仿真发现,当信号光RIN高于本振光RIN时,信号光功率越大相干平衡探测系统输出信号噪声改善效果越好,此时若本振光功率高于信号光功率,则相干平衡探测输出信号信噪比会得到改善。当激光器间存在0.1 GHz频率差时,相干平衡探测输出信号信噪比改善效果会得到提升。平衡探测法相比传统反馈法,可以有效减少外来电信号的接入,总结了平衡探测法抑制roF链路的最佳工作区域和环境,为对该方法后续的研究改进提供了实验参考。

In this paper,a coherent balance detection method is proposed to suppress the noise of ROF link output signal.By introducing local oscillator light to couple with signal light,the output light suppresses the direct current disturbance of the optical signal through a subtractor,thereby suppressing RIN,indirectly suppressing the noise of the output signal and improving the signal-to-noise ratio of the output signal.Optiisystem simulation shows that when the RIN of signal light is higher than the RIN of local oscillator,the higher the power of signal light,the better the improvement effect of output signal noise of coherent balance detection system.At this time,if the power of local oscillator is higher than that of signal light,the signal-to-noise ratio of output signal of coherent balance detection will be improved.When the frequency difference between lasers is 0.1 GHz,the signal-to-noise ratio of coherent balance detection output signal will be improved.Compared with the traditional feedback method,the balanced detector can effectively reduce the access of external electrical signals.The best working area and environment of balanced detection method to suppress roF links is summarized,which provides an experimental reference for the subsequent research and improvement of this method.