基于FPGA马赫-泽德干涉仪的光谱数据采集系统

FPGA real-time spectrum data acquisition system of Mach-Zehnder interferometer

针对马赫-泽德(M-Z)干涉仪中干涉条纹采集和处理的要求,为了使其具有高速实时光谱数据处理能力,设计了一种通过FPGA硬件编程实现干涉条纹采集处理的方法。系统由CMOS探测器采集马赫-泽德干涉仪获取的干涉图像,再将干涉图像中的灰度信息输入到FPGA芯片中,通过去噪、切趾、快速傅里叶变换、标定等求解入射激光的光谱特征。系统通过切趾加窗等处理,采用基2的快速傅里叶变换及标准波长对比的方法进行标定。在FPGA软件环境中仿真后,时序正确。硬件调试采用中心波长为580 nm,690 nm,870 nm三种激光器,由马赫-泽德干涉仪及FPGA组成的系统进行分析,实验结果与GSI8013NIR型近红外光纤光谱仪进行对比,误差小于1 nm,满足设计要求。

In order to make high-speed real-time spectrum data acquisition and processing in Mach-Zehnder interferometer,design and implement of a hardware programming in FPGA is presented.The system collected interferometer fringes of Mach-Zehnder with the CMOS detector,and then put the gray information of interference fringes into the FPGA chip.Through the noise removal,apodization,fast Fourier transform,the incident laser is calibrated.Through apodization windowing and other treatment,the system uses base-2 fast Fourier transform and the method of standard wavelength comparison to get spectrum data.In FPGA simulation software environment,the timing proves to be correct.Hardware debugging is carried out with three lasers with respectively central wavelength of 580 nm,690 nm,870 nm.The system composes of the Mach-Zehnder Interferometer and the FPGA.Results of our system are compared with the results of the GSI8013NIR fiber optic spectrometer.The error is less than ±1 nm,which meets the design requirements.