基于同相正交调制光学频域反射仪的分布式多芯光纤矢量传感

Distributed Multi-Core Fiber Vector Sensing Based on In-Phase and Quadrature Modulated Optical Frequency Domain Reflectors

针对传统光纤传感难以实现应变矢量感知的问题,设计并实验验证了基于同相正交(IQ)调制的光频域反射仪(OFDR)的多芯光纤应变矢量传感系统。使用IQ调制技术,实现了光源线性扫频,利用多芯光纤空间结构关系,在OFDR系统中获得了七芯光纤弯曲后的应变矢量信息。实验结果表明,当光源扫频范围990 MHz时,在87 m七芯光纤中,弯曲应变空间分辨率为28.35 cm。当光纤弯曲曲率为1.78 m^(−1)时,角度分辨率为29°。同时进一步通过仿真分析表明,当扫频范围提高到10 GHz时,理论上可以达到1.02°的角度分辨率,从而进一步提高系统性能。

Typically,the realization of strain vector sensing based on traditional optical fiber sensing is difficult.To address this,in this study,a multi-core optical fiber strain vector sensing system based on an in-phase and quadrature(IQ)modulated optical frequency domain reflector(OFDR)is designed and verified.The IQ modulation technique is used to perform a linear frequency sweep of the light source,and the strain vector information of a seven-core fiber after bending is obtained from the OFDR system using the spatial structure relation of multi-core fibers.Experimental results demonstrate that the spatial resolution of the bending strain is 28.35 cm in an 87 m seven-core fiber with a sweep frequency of 990 MHz.When the bending curvature of the optical fiber is 1.78 m^(−1),the angular resolution is 29°.Moreover,the simulation analysis indicates that when the sweep frequency range increases to 10 GHz,a theoretical angular resolution of 1.02°can be achieved,which can further improve the system performance.