光纤法布里-珀罗传感器偏振互相关解调系统的复消色差光路设计  

Design of Apochromatic Optical Path in Polarization Cross-Correlation Demodulation System Based on Fiber Fabry-Perot Sensor

作　　者：宋凝芳[1] 宋鹏[1] 宋镜明[1] 亢提 

机构地区：[1]北京航空航天大学仪器科学与光电工程学院,北京100191

出　　处：《中国激光》2017年第12期255-262,共8页Chinese Journal of Lasers

基　　金：国家重大科学仪器设备开发专项(2013YQ040877)

摘　　要：光纤法布里-珀罗(F-P)传感器被广泛应用于航空发动机的检测中。偏振互相关解调法是最常用的F-P腔长解调方法。在偏振互相关解调系统中,光学系统的轴向色差会引起零级干涉条纹的偏移和光强的减小,从而降低解调精度并减小信号幅值,因此分析了光学系统的轴向色差对解调的影响。为了减小光学系统的轴向色差对解调的影响,设计了一种应用于偏振互相关解调仪的复消色差光学系统。该光学系统在光楔长度方向上的轴向色差为1.9×10^(-4) m^(-1),最大光程差为0.021λ_0(λ_0为中心波长),光程差远小于F-P腔长。对于特定的解调系统,采用复消色差光路时,零级干涉条纹的测量值偏移量为2.85μm,小于CCD像素宽度的一半,并且CCD任意像素的光照度提高了3.75倍。Fiber Fabry-Perot（F-P）sensors have been widely used in the detection of aircraft engines.Polarization cross-correlation demodulation is one of the most common methods for F-P cavity length demodulation.In a polarization cross-correlation demodulation system,the axial chromatic aberration of the optical system will cause the zero-order interference fringe shift and decrease the light intensity,which decreases the demodulation accuracy and the signal amplitude.The effect of axial chromatic aberration of the optical system on demodulation is analyzed.In order to reduce the influence of the axial chromatic aberration of the system on demodulation,an apochromatic optical system used in the polarization cross-correlation demodulation interrogator is introduced.The axial chromatic aberration along the wedge length is 1.9×10^-4 m^-1,and the maximum optical path difference is 0.021λ0（λ0 is the central wavelength）,which is far less than the F-P cavity length.For a certain demodulation system,the shift of the measured zero-order interference fringe is 2.85μm,which is less than half of the pixel width of CCD,and the illuminance of any pixel of CCD is improved by 3.75 times.

关 键 词：光纤光学 光路设计 复消色差 光纤法布里-珀罗传感器 

分 类 号：TN0[电子电信—物理电子学]