光纤傅里叶变换光谱仪采样系统

提出了一种用于连续扫描光纤傅里叶变换光谱仪(FFTS)的干涉图采样系统,将激光干涉信号用Hilbert变换产生正交信号,由于相位反转点的存在,导致Hilbert变换产生的信号出现畸变,对变换结果进行了修正。该信号和原信号成为两个互相正交信号,利用这两个信号整形后的相位关系可得到光程扫描的起始点和光程扫描的方向。根据光程扫描的起始点和方向选择可上升沿部分的参考光和测试光干涉信号,用改进的Brault算法重新得到等光程间隔抽样的干涉图。该设计方法可以用DSP 技术实现简单、紧凑型的采样系统,不仅可提高FFTS的信噪比,还可以推广到传统的傅里叶光谱仪中。

Sampling system of optical fiber Fourier transform spectrometer

A novel design applying to sample system of optical Fiber Fourier Transform Spectrometer(FFTS) was proposed.Two quadrature signals,one of which comes from laser interference with Hilbert transform of another with correction after phase inversing,were generated.Using phase relation of two square waves,the initial position and the direction of OPD scanning were determined.These parameters was used to decide the portion of up-scanning of interference and test beam to abtain the uniform interval interferogram with similar Brault algorithm.A compact and simple sample system would be designed by DSP for further practice.The designing method not only can be applied to the FFTS,but also can be generalized to conventional Fourier transform spectrometer.