光源谱型对保偏光纤应力传感信号的影响

保偏光纤对入射的线偏振光具有偏振保持能力,用白光干涉系统可实现准分布式应力、温度和位置传感。超辐射发光二极管(SLD)当驱动电流较小时,光谱服从高斯分布;随着驱动电流增加,中心波长向短波方向漂移,光谱畸变,可用两个高斯函数相加拟合。本文详细分析了SLD光源在不同驱动电流下的谱型分布及拟合曲线,并在保偏光纤应力传感系统中进行了实验,实验结果表明随着光源输出功率增加,在耦合点两侧对称分布着伪耦合点。当光源功率为15 mW时,伪耦合点的耦合强度比力致耦合点的耦合强度约小15 dB。

Influence of light source spectrum distribution on polarization maintaining fiber stress sensing signal

Polarization maintaining fiber(PMF)where the linear polarization state is forcedly maintained,can realize quasi-distributed stress sensing,temperature sensing,position sensing based on white-light interferometry sensing system.The spectrum of superluminescent diode(SLD)follows the gauss distribution,when the driving current of SLD is low.With the increasing of driving current,the central wavelength will decrease.Spectrum can be fitted with the sum of two gauss function.The spectrum distribution and fitting function are analyzed at different driving current.Experiments are conducted in PMF stress sensing system.Experimental results show that false coupling points will distribute symmetrically at two sides of coupling points induced by stress,with the driving current increasing.When the output power of light source is 15 mW,the intensity of false coupling points is 15 dB less than the intensity of coupling point induced by stress.