WDM与OTDR结合的弱光栅分布式温度传感网络

提出一种基于弱反射布拉格光栅的新型分布式温度传感网络,将WDM与OTDR相结合,采用WDM技术提高光栅的复用容量,利用OTDR对各个弱光栅进行实时检测,以实现光栅的密集串行复用,并提高空间分辨率。使用可调谐脉冲激光为光源,多组不同中心波长弱光栅等间距刻制在一根光纤上。利用一根光纤刻制的三组反射率为3%,中心波长分别为1544.660nm、1545.802nm和1546.900nm的9个FBG进行了温度实验。实验结果表明,在5～80℃的温度范围内,FBG的中心波长随温度变化呈良好的线性,线性度达到99.6%以上,温度测量的分辨率最高达到0.11℃,空间分辨率可达2m。

Distributed Temperature Sensor System Based on Weak Reflection Fiber Gratings Combined with WDM and OTDR

Based on a weak reflection Bragg grating, a new distributed temperature sensing network is proposed by combining Wavelength Division Multiplexing (WDM) with Optical Time-domain Reflectometry (OTDR). WDM technology is used to enhance the FBG multiplexing capacity, and OTDR is used for each weak grating for real-time detection, so as to realize the intensive serial multiplexed grating and improve the spatial resolution. Using the tunable pulsed laser as the light source, multiple groups of different center wavelength grating are engraved in weak isometric in one fiber. Reflectivity of three groups is 3%. The center wavelengths are 1 544.660 nm, 1 545.802 nm and 1 546.900 nm three FBG, divided into three groups. In one fiber, quasi-distributed measurement is realized. Experimental results show that, in 5~80℃ temperature range, FBG center wavelength with temperature change shows good linearity, linearity reaching more than 99.6%, the temperature measurement resolution of up to 0.11℃, a spatial resolution of 2 m.