基于相干包络解调的窄线宽测量算法研究

Narrow Laser Linewidth Measurement Based on Coherent Envelope Demodulation

摘要:

激光线宽对光学相干探测系统的探测范围、精度和噪声特性都有重要影响。为精确测量半导体激光器的线宽值,提出了通过解调短延时自外差的干涉谱来实现高精度窄激光线宽测量的新方法。搭建短延时的自外差干涉测量系统,得到半导体激光器的干涉谱,通过设计算法对干涉谱的相干包络进行解调,最终获得了严格的洛伦兹线型谱和相应的谱线宽度,通过理论分析、仿真和实验验证了该方法的可行性。该方法可以忽略因1/f频率噪声产生高斯展宽带来的影响,与传统线宽测量方法相比,该方法的测量结果更加精确。

Abstract:

Laser linewidth puts great effect on the detection range, precision and noise characteristics of the optical coherent detection system. To improve the measurement accuracy of laser linewidth, a new method was proposed based on demodulating the interference spectrum of short delay self-heterodyne. The interference spectrum was obtained by building a short delay self-heterodyne interferometry system. An iterative algorithm was designed to demodulate the coherent envelope of the interference spectrum, and then strict Lorentzian spectrum and the corresponding linewidth were obtained. The feasibility of this method was verified by theoretical analysis, simulation and experiments. Compared to the conventional methods, the proposed method can ignore the influence of the Gaussian broadening caused by laser 1/f frequency noise.