基于非切趾短FBG光栅的小信号测量方法

为解决基于图像传感器的FBG解调系统精细测量的问题,提出了使用非切趾FBG测量弱信号的方法。设计出了非切趾FBG反射谱近似模型,采用对数放大的方法提高非切趾FBG的旁瓣,在较宽的光栅频谱范围内,进行光谱相关解调并给出解调算法。基于蒙特卡洛方法对非切趾光栅测量仿真,并搭建实验系统对非切趾FBG、宽带高斯光栅进行对比测量实验。研究结果表明,基于非切趾FBG的弱信号测量方法可有效提高波长测量精度,通过相关解调,可使测量精度达到宽带光栅的2倍。

Weak signal measurement method based on short non apodized FBG

In order to solve the problem of fine measurement of FBG demodulation system in image sensor,a weak signal measurement method based on non apodized FBG is proposed.A non apodized FBG reflection spectrum approximation model was established,and the method of logarithmic amplification was used to improve the sidelobe of non apodized grating,the spectral was demodulated in a wide range of grating spectrum and the demodulation algorithm was given.Based on the Monte Carlo method,the non apodization grating was measured and simulated,and the experimental system was built to compare the measurement of the non apodization grating and the wide spectrum Gauss grating.The results show that the measurement method of weak signal based on non apodized FBG can effectively improve the accuracy of wavelength measurement.By correlation demodulation,the measurement accuracy can reach 2 times of wide spectrum grating.