基于相位调制-解调的光纤激光相位噪声检测方法研究

在主动相位控制相干合成中,常用的光纤激光主动相位控制方法主要有外差法、多抖动法和随机并行梯度下降算法等. 基于多抖动法和外差法的原理,提出了一种新型的基于相位调制-解调的相位检测与控制方法. 该方法利用周期信号对参考光进行相位调制,将调制后的参考光与待检测信号光进行相干检测,通过对相干光强信号和相位调制信号的融合处理,实现相位噪声的检测和控制. 对该方法进行了数值模拟和实验研究. 实验结果表明,对于频率为2 kHz,噪声范围为[0,2π)的正弦噪声,相位检测精度优于λ/50,控制精度可达关键词：光纤激光相干合成相位噪声检测调制-解调

Phase noise detection method in fiber lasers based onphase modulation and demodulation

In coherent combination of active phase control, there have existed three main phase detection techniques until now, they are heterodyne phase detection technique, multi-dithering technique and stochastic parallel gradient descent algorithm. A new phase detection method based on phase modulation and demodulation is proposed according to the principle of heterodyne phase detection and multi-dithering technique. Periodic phase modulation signal is implemented on a reference laser, and the coherent detection is carried on between the reference laser and the signal laser. With some processing of the modulation signal and the coherent detected optoelectronic signal, the phase noise is detected and the noise compensation can be realized. Numerical simulation and experimental studies are conducated. Experimental results show that the phase detection accuracy is higher than 1/50 wavelength and the average phase compensation residual error is less than 1/50 wavelength in the case of a 2 kHz sine wave phase noise with a phase region of