光克尔效应提高全光纤前端系统信噪比的理论分析

Theory analysis on improving SNR of all-fiber front end system by optical Kerr effect

为了提高高功率激光装置全光纤前端系统的信噪比,提出了光克尔效应抑制噪声的方法,并对其进行了理论分析。根据理论分析,设计了脉冲净化单元。计算结果表明:采用光克尔效应脉冲净化单元可以使信噪比提高3个数量级。分别研究了带有基座的高斯脉冲和方波脉冲经过脉冲净化单元后,可以有效地滤除基座,从而达到提高信噪比的目的。同时研究了不同峰值功率的高斯脉冲和方波脉冲经过脉冲净化单元后的功率分布及透过率。结果显示,经过脉冲净化单元,高斯脉冲的半宽度变窄,而方波脉冲可以有效地克服这种脉冲窄化,其能量透过率要高于高斯脉冲的透过率。

In order to improve the signal-to-noise ratio （SNR） of all-fiber front end for high-energy laser device, a method to restrain the noise by optical Kerr effect was proposed, and its theory was analyzed in this paper. Based on the analysis, the cell of pulse cleaning was designed. Numerical calculation indicates that the SNR can be increased by 3 magnitudes with the cell ＂of pulse cleaning. The transmissivity for the Gauss pulse and square pulse with the pedestal through the cell of pulse cleaning were studied. The results indicate that the pedestal can be filtered, and SNR can be improved markedly. Meanwhile, the distributions of output power and transmissivity for Gauss pulse and square pulse through the cell of pulse cleaning were studied. The results show that the half width of Gauss pulse gets narrow after the cell of pulse cleaning, but the square pulse does not, and the transmission of Gauss pulse energy is lower than the square pulse.