基于三次样条插值的光纤F-P传感器傅里叶变换解调研究

从傅里叶变换原理入手,对不插值傅里叶变换解调和高斯频谱插值方法的误差进行了分析.介绍了三次样条插值的原理,通过三次样条插值得到输出光强信号对光频率均匀采样光谱.从光纤F-P传感器的腔长由20 μm以0.02 μm步长匀速增加至120 μm的仿真分析得出,经过三次样条插值后再进行傅里叶变换解调的精度相对频率插值法更高.在此基础上,采用美国Ocean Optics公司生产的USB2000型光谱仪和Melles Griot公司的17MAX600型光纤对准微动台(精度达0.01 μm)搭建了实验系统并进行了对比实验.结果表明,基于三次样条插值的傅里叶变换解调方法误差在0.06 μm以内.

Demodulation Method Based on Fourier Transform with Cubic Spline Interpolation for Optical Fiber Fabry-Perot Sensors

Based on principle of Fourier transform method error caused by Fourier transform without interpolation and Gaussian interpolation in frequency domain are analyzed. Then cubic spline interpolation is introduced, and even sampling of intensity in optical frequency domain is obtained with this interpolation. Simulation analysis is carried out when gap length of optical fiber Fabry-Perot sensor is growing from 20 μm to 120 μm with 0.02 μm step. Results from simulation show that precision of Fourier transform method with cubic spline interpolation is much better than Gaussian interpolation in frequency domain after Fourier transform. Experimental result shows that: error caused by Fourier transform method with cubic spline interpolation is less in 0.06 μm.