双光束干涉型光纤传感器灵敏度与精度受光源谱分布特性的影响分析

Effect of spectrum distribution of light source on sensitivity and precision of two-beam interferometric optic-fiber sensor

基于对双光束干涉型光纤传感器原理的分析,针对洛仑兹、高斯、矩形3种典型光源谱分布,通过对谱分布线宽与光电管接收端功率谱密度之间关系的定量分析,讨论了3种典型光源谱分布特性对传感器灵敏度的影响。假设光场为稳态、遍历随机过程,定量分析了光源谱线宽与接收端相位改变量之间的关系,对比了3种光源谱特性对于传感器精度的影响。结果表明:当时延小于阈值时,采用洛仑兹光源谱的传感器灵敏度最大;当时延大于阈值时,采用矩形光源谱的传感器灵敏度随时延呈周期振荡变化。同时,3种光源谱分布下,洛仑兹光源谱分布线宽对传感器精度的影响最大,矩形光源谱分布线宽对传感器精度的影响最小。

The theory of two-beam interferometric optic-fiber sensor was discussed.For three typical spectrum distributions such as Lorentz,Gauss and rectangular,based on the analysis of quantitative relation between light source line-width and the power spectral density of phototube receiving end,the effects of three light sources on sensitivity were discussed.Based on the hypothesis of ergodic random and steady-state light field,the quantitative relation between light source line-width and the phase change of phototube receiving end was analyzed,and the effects of three typical light sources on precision of sensor were compared.The results show that during three typical spectrum distribution,when time delay is less than the threshold,the optic-fiber sensor with light source of Lorentz has the highest sensitivity,and when time delay is more than the threshold,the optic-fiber sensor with light source of rectangular is oscillatory periodically.The light source line-width of Lorentz has the greatest effect on the precision of sensor while that of rectangular has the least effect on the precision of sensor.