采用MOPA结构的光学外差干涉激光器

Optical heterodyne interference laser based on MOPA structure

为了满足激光干涉成像,尤其是傅里叶望远镜成像对差频稳定的高功率光学外差干涉模式的需要,提出基于主振功放(MOPA)结构的光学外差干涉激光器的概念,并通过实验验证可行性。从原理上指出现有产生光学外差干涉模式方法的局限性,同时给出基于MOPA结构的光学外差干涉激光器的主要优点。指出基于MOPA结构的激光器可能存在明显影响相干性和产生光频漂移等的限制并设计实验验证。结果表明:功率放大过程对相干性没有明显影响,经过单级功放仍能保持线宽小于0.1GHz(根据实测相干长度计算线宽约30MHz),功放过程和倍频过程对光频漂移无影响,实测频漂小于10Hz,与声光移频器的频率稳定性相吻合,故推知频漂完全由移频器引起。

In order to satisfy the requirement of laser interference imaging, especially Fourier telescope imaging, to generate frequency-stably high-power optical heterodyne interference mode, the concept of optical heterodyne interference laser based on the structure of MOPA was put forward and was proved by experiment. The limits of conventional method of generating optical heterodyne interference mode were pointed out and the main merits of optical heterodyne interference laser based on the structure of MOPA were presented. The possible limits of obvious effects on interference and inducing optical excursion were pointed out and were proved by experiment. The conclusion is given that the process of power amplification has no effect on interference and the line width is less than 0.1GHz by single amplification （based on real measurement of coherent length, the line width is about 30 MHz）,and also that the processes of power amplification and frequency doubling has no effects on optical excursion and it is deduced that the real measurement of frequency excursion less that 10 Hz coinciding with frequency stability of AO frequency shifter was only related with frequency shifter.