长周期光纤光栅-布拉格光纤光栅多波长解调

Multiple Wavelength Demodulation Method of Long Period Fiber Grating and Fiber Bragg Grating

提出了一种长周期光纤光栅(Long Period Fiber Grating,LPFG)-布拉格光纤光栅(Fiber Bragg Grating,FBG)多波长解调方法。FBG能够反射LPFG透射光,FBG中心波长的漂移会引起反射光功率的变化,进而改变光电转换电压,从而实现电压对中心波长的解调。由于LPFG的带宽很宽,而FBG的带宽很窄,进而一个LPFG可以实现对多个FBG的解调。实验结果表明:FBG的中心波长和光电转换后的电压有良好的对应关系。该解调方法结构简单,测量精度高,能够实现对温度、应力等参数的多点测量。

A multiple wavelength demodulation method of long period fiber grating and fiber Bragg grating is proposed. Fiber Bragg grating can reflect the long period fiber grating transmission light. The central wavelength shift of fiber Bragg grating will cause the change of reflected light power, and the photoelectric conversion voltage can also change accordingly. So the voltage can demodulate the central wavelength. Because the transmission spectrum of long period fiber grating is very wide, the bandwidth of fiber Bragg grating is so narrow, and a long period fiber grating can demodulate a lot of fiber Bragg gratings. The experimental results show that the voltage of central wavelength and the photoelectric conversion of fiber Bragg grating have a good corresponding relationship. The demodulation method has some advantages including simple structure and high accuracy, so it can be used to measure the parameters of temperature and strain.