无线光外差检测系统研究与仿真

本文提出了一种新的基于副载波调制的无线光外差检测方案,用Optisystem对其进行仿真,计算了系统的外差增益,分析了影响无线光外差检测系统外差增益的几个主要因素,包括信号光的偏振态、激光器线宽、本振光功率及调制速率。从仿真结果可以得出：若信号光和本振光的偏振态不一致,会导致外差增益的下降;接收机灵敏度随光源激光器线宽的增大而降低,误码率要达到10-9,线宽最大不超过25KHz;增大本振光功率可以提高灵敏度,但这个提高不是无限地,存在一个最佳本振光功率,如果大于这个最佳值,信噪比反而会降低。

Research and simulation of wireless optical heterodyne detection

This paper presents a new optical heterodyne detection scheme based on subcarrier modulation,it is simulated by Optisystem.Heterodyne Gain has been calculated in this paper.Main factors affecting the system including polarization state of signal optical,laser line width and local optical power has been analyzed.Simulation results show that heterodyne gain decreases if polarization state of signal optical and local optical are not in the same direction.When two beams are both linear polarization,the maximum gain is 11.64389dB which is in coincident with theory.The sensitivity of receiver is reduced with laser line width increasing,BER reaches 10-9 and maximun line width is not beyond 25KHz.Increasing of local optical power can improve sensitivity,but the increase is finite.A best local optical power exists.When the power is bigger than the best one,however SNR is reduced.