基于可调谐激光器的光纤光栅波长解调系统误差分析与补偿

基于可调谐激光器的光纤(Bragg)光栅(FBG)波长解 调系统性能受激光器控制电路、调制参数以及光电探测器(PD)性 能、弱信号采集与放大电路等诸多因素的影响,着重研究了可调谐激光器调制参数中扫描频 率对光栅波长 解调系统的影响,发现波长解调误差随扫描频率的不同而呈现一定的规律,对波长解调误 差与激光器的 扫描频率进行了拟合。将拟合结果植入解调程序中,对激光器当前扫描频率下的解调波长进 行实时误差补 偿,并实验验证了误差补偿后的效果。结果表明,进行误差补偿后系统最大波长解调误差比 之前减小6.0 倍,其中由激光器扫描频率不同导致的波长解调误差和均方差(SD)分别比补偿之前减小2.2倍。最 终 使得基于可调谐激光器的FBG波长解调系统整体波长解调误差控制在1.38pm以内,有效地满足了高 速FBG系统对解调波长准确性和稳定性的要求,适用于高频动态信号的解调。

The error analysis and compensation of fiber Bragg grating wavelength demodulation system based on tunable laser

The performance of fiber Bragg grating (FBG) wavelength demodulation system based on tunable laser is affected by many factors,such as the control circuit and modulation pa rameter of laser, performance of photodetector,acquisition and amplification circuit of weak sign al.Scanning frequency is one of the most important parameters in laser modulation,and its effects on the FBG wavelength demodulation system are studied.This paper finds that the error of wavelength de modulation varies with the scanning frequency.In this paper,the error of wavelength demodulation and the scanning frequency of the laser are fitted,and the fitting results are embedded into the demodulat ion program to compensate the real-time error of the demodulation wavelength under the current laser scan ning frequency.The effect of error compensation is verified by experiments.The results show that t he maximum error of wavelength demodulation is improved by 6.0times and the error of wavelength dem odulation and standard deviation (SD) caused by laser scanning frequency are respectively reduced by 2.2times and 1.9times.Finally,the demodulation error of FBG wavelength demodulation system based on tunable laser is limited to 1.38pm,which it can effectively meet the accuracy and stability of demodulation wavelength in high-speed FBG wavelength demodulation system,and can be used in the demodulation of high-fre quency dynamic signal.