长周期光纤光栅对结构参数的敏感特性

Sensitive properties of a long period fiber grating to structural parameters

基于模式耦合理论,对影响长周期光纤光栅(LPFG)光谱特性的各种物理结构参数进行了研究,得到LPFG光谱特性响应的一系列定量或定性的规律。利用紫外线,通过振幅掩模法曝光H载掺Ge光纤制作了两根LPFG,写入的光栅长度分别为3.0 cm和4.5 cm,测得温度灵敏度分别为0.044 6 nm/℃和0.059 4 nm/℃,结果表明,在其它参数相同的情况下,长度较长的LPFG损耗峰深度较大、带宽较窄,其灵敏度相应较高。

The various physical parameters which impact the long period fiber grating（LPFG） spectral characteristics are analyzed comprehensively based on the mode coupling theory in this paper.The quantitative or qualitative results of LPFG spectral characteristics,which can provide the theoretical basis for LPFG design and parameter optimization,are obtained.Two long-period fiber gratings with lengths of 3.09 cm and 4.5 cm are fabricated by the amplitude mask method,in which the germanium-doped fiber is exposed by the UV light.The temperature sensitivities are measured to be 0.044 6 nm/℃ and 0.059 4 nm/℃,respectively.We can see that when the other parameters are equal,the longer the long-period fiber grating,the deeper the loss peak,the narrower the bandwidth,and the higher the sensitivity.