Zhao Zhongan, Bai Zhenxu, Jin Duo, Chen Xiaojing, Qi Yaoyao, Ding Jie, Yan Bingzheng, Wang Yulei, Lu Zhiwei, Mildren Richard P
Center for Advanced Laser Technology, Hebei University of Technology, Tianjin 300401, China.
Hebei Key Laboratory of Advanced Laser Technology and Equipment, Tianjin 300401, China.
Micromachines (Basel). 2022 Aug 13;13(8):1311. doi: 10.3390/mi13081311.
Delayed self-heterodyne/homodyne measurements based on an unbalanced interferometer are the most used methods for measuring the linewidth of narrow-linewidth lasers. They typically require the service of a delay of six times (or greater) than the laser coherence time to guarantee the Lorentzian characteristics of the beat notes. Otherwise, the beat notes are displayed as a coherent envelope. The linewidth cannot be directly determined from the coherence envelope. However, measuring narrow linewidths using traditional methods introduces significant errors due to the 1/ frequency noise. Here, a short fiber-based linewidth measurement scheme was proposed, and the influence of the noise floor on the measurement of the laser linewidth using this scheme was studied theoretically and experimentally. The results showed that this solution and calibration process is capable of significantly improving the measurement accuracy of narrow linewidth.
基于不平衡干涉仪的延迟自外差/零差测量是测量窄线宽激光器线宽最常用的方法。它们通常需要延迟六倍（或更大）于激光相干时间，以保证拍频信号的洛伦兹特性。否则，拍频信号将显示为相干包络。线宽不能直接从相干包络中确定。然而，使用传统方法测量窄线宽时，由于1/频率噪声会引入显著误差。在此，提出了一种基于短光纤的线宽测量方案，并从理论和实验上研究了本底噪声对使用该方案测量激光线宽的影响。结果表明，该解决方案和校准过程能够显著提高窄线宽的测量精度。
