基于DPMZM的微波光子倍频激光雷达仿真分析

Simulation and analysis of LiDAR based on DPMZM and microwave photonic frequency multiplication

为了提升调频连续波激光雷达调制带宽、从而提高距离分辨率,采用基于双平行Mach-Zehnder调制器的外调制方式,结合无光滤波器的微波光子倍频技术,通过1 GHz的射频源实现8 GHz的宽带射频调制信号,并利用搭建的模型研究了微波光子倍频子系统中消光比、调制系数和移相器相位偏移3个参数的变化对调频连续波激光雷达系统性能的影响。结果表明,大部分商用调制器的消光比可以满足使用需求,调制系数在2.385~2.425范围内或电移相器误差不大于1.3°时,该激光雷达探测信号峰的功率抑制比可以保持在20 dB以上。此研究结果为微波光子倍频技术在调频连续波激光雷达中的应用提供了理论支持,对工程实现有一定的参考意义。

In order to increase the modulation bandwidth of frequency-modulated continuous wave(FMCW)light detection and ranging(LiDAR)for the high range resolution,with the use of external modulation mode based on dual-parallel Mach-Zehnder modulator(DPMZM),combined with the microwave photonic frequency multiplication technology where no optical filters were used,the broadband radio frequency(RF)modulated signal of 8 GHz was realized from a 1 GHz RF source.Furthermore,the effect of the variation of three parameters in the subsystem,namely extinction ratio,modulation index,and phase shift of phase shifter,on the performance of the built FMCW LiDAR system model was investigated.The results show that the extinction ratio of most commercial modulators can meet the requirements of use.When the modulation index is in the range of 2.385~2.425 or the electrical phase shifter error is not greater than 1.3°,the suppressed ratio of FMCW LiDAR detection signal peak power can be maintained above 20 dB.These researches provide theoretical support for the application of microwave photonic frequency multiplication technique in FMCW LiDAR and have certain reference significance for engineering implementation.