光束分束比对2μm平衡式相干探测系统信噪比影响的实验研究  

Experimental Investigation for Relation between Beam Splitter Coefficient and Signal-to-Noise Ratio of 2 μm Balanced Coherent System

作　　者：王春晖[1] 高龙[1] 庞亚军[1] 刘磊[1] 李彦超[1] 曲杨[1] 

机构地区：[1]哈尔滨工业大学可调谐激光技术国家级重点实验室,黑龙江哈尔滨150001

出　　处：《光学学报》2011年第11期53-58,共6页Acta Optica Sinica

基　　金：国家自然科学基金(61078063);中央高校基本科研业务费专项资金资助课题

摘　　要：给出了平衡式相干探测系统的一般信噪比数学模型,对该数学模型和普通单源相干探测系统的信噪比模型进行了数值仿真对比研究。仿真结果表明,当平衡式相干探测系统中的光电探测器理想匹配时,其系统的信噪比以分束比系数等于0.5呈对称分布;而当光电探测器失配时,系统的最大信噪比所对应的最佳光束分束比发生偏离。最后搭建了2μm平衡式相干探测实验系统,实验结果表明,在相同的输入光功率下,平衡式相干探测系统的最大信噪比比普通单源相干探测系统的信噪比高19dB;平衡式相干探测系统的信噪比趋于饱和的范围比普通相干探测系统趋于饱和的范围宽大约0.2。Mathematical model of signal-to-noise ratio （SNR） for balanced coherent system is proposed and SNR of balanced coherent system is simulated analytically with that of conventional coherent system. Simulation results show that SNR of balanced coherent system is symmetrical with 0.5 beam splitter coefficient with the matched detectors. Whereas, the optimum beam splitter coefficient for maximum of SNR is deviated from 0. 5 with the unmatched detectors. Experimental configuration for 2 ~m balanced coherent detection is demonstrated in which the SNR is more than 19 dB higher than that of conventional coherent system with 0.5 beam-splitter coefficient and the range for SNR of balanced coherent detection near to saturation is more than 0.2 wider than that of conventional coherent system under the same optical power condition.

关 键 词：光学测量 平衡式相干探测 光束分束比 量子效率 散粒噪声 

分 类 号：O436.3[机械工程—光学工程]