一种新颖的高灵敏度光纤光栅带宽调谐机构

设计了一种由一直梁和两个半圆拱组成的开口环结构，并将均匀光纤布拉格光栅斜贴于直梁中间的表面处。对两半圆拱施加与直梁方向平行的应力作用时，光纤光栅受到线性应力场的作用，光纤布拉格光栅即转化为啁啾光纤光栅。该机构实现了光纤光栅带宽的线性调谐，线性度高达0．9982，实验结果与理论分析一致。与以往的带宽调谐机构相比，该机构具有很高的应力灵敏度，在20N力的作用下，可产生约7nm的带宽反射，灵敏度达0．34nm／N。利用环境温度对带宽调谐无影响的特性，采用带宽编码技术，研制出具有温度自动补偿特性、高灵敏度的带宽调谐装置。

A Novel High-Sensitivity Chirp Tuning Device of Fiber Grating

A novel and simple chirp tuning device of fiber Bragg grating(FBG) is proposed,which possesses a "C" shape and consists of a straight beam and two half-round arches.A linear strain field is induced over the straight beam by applying stress on the arches.As a result,the uniform FBG bonded on the surface of the beam is converted to a linearly chirped fiber grating.The bandwidth of the FBG is tuned linearly by applied stress with the sensitivity up to 0.34 nm/N and a linearity of 0.9982.In the experiment,a chirp bandwidth of about 7 nm can be obtained with the stress of 20 N.Additionally,the reflective spectra are quite flat.The experimental results are in good agreement with the analyses.Due to the characteristic of the bandwidth immunity to environmental temperature variation and large tunable range of bandwidth,the device can be applied in fields such as measurement of stress(strain,curvature,etc.),fiber laser,chromatic dispersion compensation.