基于内置电光晶体的Mach-Zehnder干涉仪，利用Mach-Zehnder干涉仪双光束干涉原理和晶体的线性电光效应，提出了一种新的能有效提高啁啾脉冲信噪比的扫描滤波方法。定量分析了其扫描滤波谱特性，探讨了预脉冲噪声延时对信噪比提升效果的影响，并讨论了电光晶体的电压控制参数对信噪比提升效果的影响。研究结果表明：预脉冲噪声的延时和控制电压的变化会对滤波效果产生较大影响，利用该扫描滤波方法可将啁啾脉冲激光信噪比提升约2个量级，且信号光透过率高达95%以上。

Based on Mach-Zehnder interferometer placed in electro-optic crystal, and using the principles of double beam interference of the Mach-Zehnder interferometer and the linear electro-optic effect of the crystal, a new method of scanning filtering for improving the signal to noise ratio (SNR) of chirped pulse was proposed. The spectral characteristics of the scanning filter were analyzed quantitatively. The effects of the delay time of the prepulse on the output SNR were analyzed. Moreover, the effects of the control parameters of the electro-optic crystal voltage on the SNR were discussed in detail. The results show that the variation of controlling voltage and the delay time of the prepulse have significant impact on the filtering effect and that the SNR of the chirp pulse can be improved nearly two magnitudes by using the scanning filtering method and the transmittance of signal can be as high as 95% or more.