短光纤延时自外差法测量窄线宽激光器线宽

Short fibre delayed self-heterodyne interferometer for ultranarrow laser linewidth measurement

从理论上分析推导了移频延时自外差法测量激光器线宽的基本原理,并采用延时自外差法数学模型,编写了仿真程序.借助此分析结果,通过对两台已知线宽的窄线宽激光器的实际测量数据,与仿真结果对比,验证了模型的正确性.在此基础上,提出了短光纤延时自外差法,采用该方法可以在延时光纤长度远小于6倍的激光器相干长度时,消除延时自外差法因为延时时间不够导致测量精度的大幅度下降这一缺陷,为工程上实现精确测量窄线宽激光器线宽提供了行之有效的方法.

Ultranarrow laser linewidth measurement using an shorter delay fibre to realize delayed self-heterodyne interferometer was described. The fundamental using delayed self-heterodyne to measure laser linewidth was analyzed, and the emulator was programmed based on the mathematical module. An experimental setup was constructed to measure subkilohertz laser linewidths, the experimental results agree well with the emulational result. On the basis analysis, the method of short fibre delayed self-heterodyne were presented and analyzed. By using the method, the measure error can be decreased greatly when the length of delay fibre shorter than six times laser＇s coherence length. It is proved that method is an effective tool for measuring an ultranarrow laser linewidth, and it can reduce the length of fibre.