基于声光效应的相干探测光学降噪方法研究

Research on Noise Cancellation Based on Acousto-Optic Effect in Coherent Detection

研究声光效应光栅理论,分析动量匹配与衍射效率关系,探讨相干光平衡探测的噪声抑制机理,进行了系统设计和相关实验测试,验证基于声光效应的相干平衡探测系统光学降噪方法的技术实现。结果表明,相位确定的信号在进行声光互作用时能建立稳定光栅,其衍射效率将大于相位随机变化的噪声信号,通过平衡探测可有效抑制噪声起伏对系统输出的影响,进一步提高接收信噪比。

The grating theory of acousto-optic effect grating is studied. The relationship between momentum matching and diffraction efficiency is analyzed. The noise reduction mechanism of balance coherent detection is discussed. The system is designed and the relative experiment is test. Noise reduction technology based on acousto-optic effect in coherent balanced detection is verified. The result shows that in the interaction of the sound and light,a stable grating could be established when the phase of signal is determined, and its diffraction efficiency is bigger than noise signal whose phase is random. By using balance detection, the influence of noise fluctuation to the system output is effective inhibited, and the signal noise ratio is improved.