摘要
Rayleigh backscattering enhancement(RSE)of optical fibers is an effective means to improve the performance of distributed optical fiber sensing.Femtosecond laser direct-writing techniques have been used to modulate the fiber core for RSE.However,in-core modulation loses more transmission light,thus limiting the sensing distance.In this work,a cladding-type RSE(cl-RSE)structure is proposed,where the femtosecond laser is focused in the fiber cladding and an array of scatterers is written parallel to the core.The refractive-index modulation structure redistributes the light in the cladding,and the backward scattered light is recovered,which enhances the Rayleigh backscattered signal with almost no effect on the core light.
基金
National Natural Science Foundation of China(61927812,62075181,62305269)。
