基于光频域反射的总线型拓扑结构FBG传感网络

为了提高光纤光栅(FBG)传感系统的传感容量以及传感器的实际工程生存能力和后期可维护性,提出了一种基于光频域反射(OFDR)技术的总线型拓扑结构的FBG传感系统。利用OFDR技术,采用相同波长的FBG传感器,克服了光源带宽对系统传感容量的限制,极大提高了系统的传感器复用能力和空间分辨率。与传统的采用弱反射率FBG串联组网相比,本文系统采用强反射率FBG和光分路器实现总线型拓扑结构,在提高传感器的生存能力的同时,克服了串接式FBG传感网络中存在的多重反射和光谱阴影对测量精度的影响。温度实验表明,系统的波长重复性为±4pm。

FBG sensing network with bus topological structure based on optical frequency domain reflectometry

In order to improve the sensing capacity of the FBG sensing system and the practical engineering viability and the future maintainability of the sensors,a new FBG sensing syste m with bus topological structure based on the optical frequency domain reflectometry (OFDR) technique has been pr oposed in this paper,and in this newly presented sensing system,the sensors multiplexing capacity and spatial re solution of the sensing system can be significantly enhanced by the employment of the OFDR technique.With this t echnique,the FBG sensors with the same wavelength have overcome the limitation brought by the impact of the bandwidth of the light source on the sensing capacity.Compared with the traditional system where the ne tworking is cascaded by FBG with weak reflectivity,this newly proposed system with fiber Bragg grating has st rong reflectivity and the optical branching device is applied so as to achieve bus topological structure for the FBG sensing system which can not only improve the viability of sensor but also overcome the impacts of multiple reflections and spectrum shadow occurring in the cascading FBG sensing network on measuremen t accuracy.The results of the temperature experiment show that the wave length repeatability is ±4pm.