基于3×3干涉仪和相位信号解调的信号采样对激光噪声的影响  

Effect of signal sampling on laser noise based on 3×3 interferometer and phase signal demodulation

作　　者：李光波 延凤平[1] 秦齐 周凌云 刘艳[1] 冯亭 LI Guangbo;YAN Fengping;QIN Qi;ZHOU Lingyun;LIU Yan;FENG Ting(School of Electronic and Information Engineering,Beijing Jiaotong University,Beijing 100044,China;Photonics Information Innovation Center,College of Physics Science&Technology,Hebei University,Baoding 071002,China)

机构地区：[1]北京交通大学电子信息工程学院,北京100044 [2]河北大学物理科学与技术学院光信息技术创新中心,河北保定071002

出　　处：《光学精密工程》2023年第7期982-991,共10页Optics and Precision Engineering

基　　金：国家自然科学基金资助项目(No.61827818,No.61975009,No.61975049)。

摘　　要：提出了一种基于3×3耦合器的非平衡迈克尔逊干涉仪和相位信号解调的激光器线宽测量系统,基于相位信号解调的微分交叉相乘算法,可对所采信号进行高速实时处理,快速给出待测激光器的频率噪声信息和线宽值。该系统光路结构简单,无须主动控制,测量结果重复性高。考虑采样信号是否同时包含源信号的最大值和最小值这一重要问题,在仿真和实验两种情况下着重讨论了对源信号进行采样窗口为0.5,0.4,0.1,0.05和0.01 s的采样对所测试激光器频率噪声功率谱密度的影响。仿真和实验均表明,使用采样窗口为0.1,0.05和0.01 s未同时包含源信号的最大值和最小值的采样信号计算获得的激光频率噪声功率谱密度幅值偏高。进一步使用β-分割线法对1.5μm波段商用激光器和实验室自制的2μm波段激光器进行线宽测量验证,结果表明,使用同时包含源信号最大值和最小值的采样信号处理得到1.5μm波段商用激光器的线宽值在测量时间为2 ms时为5 kHz,同时本结论可拓展至全波段适用。A laser linewidth measurement system based on an unbalanced Michelson interferometer achieved using a 3×3 coupler and phase signal demodulation is reported in this study.The signal processing section is based on phase signal demodulation technology,which can process the signal in real time and at high speed.Therefore,the frequency noise and linewidth of the laser under test could be obtained quickly.The system features a simple optical path structure,no active control,and stable repeatability of measurement results.However,it is necessary to consider whether the sampled signal contains the maximum and minimum values of the source signal simultaneously when using this scheme.Therefore,the effect on the frequency noise power spectral density of the laser under test is thoroughly discussed with respect to different sampling windows of 0.5,0.4,0.1,0.05,and 0.01 s.Both simulation and experiment show that the amplitude of the laser frequency noise power spectral density calculated by the signal is too high,and that sampling signals with sampling windows of 0.1,0.05,and 0.01 s do not contain the maximum and minimum of the source signal.A commercial laser with a wavelength of 1.5μm and a self-made laser in our laboratory with a wavelength of 2μm are measured usingβ-separation line method.The results show that the linewidth of the commercial laser in the 1.5μm band is 5 kHz,with a measurement time of 2 ms.It also shows that this conclusion can be extended to the entire band.

关 键 词：单频窄线宽激光器 线宽测量 频率噪声 相位信号解调 

分 类 号：TN248[电子电信—物理电子学]