光纤光栅温度与轴向应变响应机制分析

本文对温度和轴向应变对长周期光纤光栅和Bragg光纤光栅耦合波长的影响机制作出分析,通过有代表性的举例计算数值给出了各因素对耦合波长的影响,指出轴向应变对耦合波长的影响除了来自光弹性效应带来的光纤折射率的改变外,光纤半径的变化,特别是光栅周期的改变也起重要作用.对比分析找到了长周期光纤光栅与Bragg光纤光栅温度,应变响应系数数量级异同的原因.

RESPONSIVE MECHANISM OF FIBER GRATINGS TO TEMPERATURE AND AXIAL STRAIN

The function mechanism of temperature and axial strain tolong-perild fiber gratings and fiber Bragg gratings′ coupling wavelengths is analyzed.Representative calculations give out all elements′ affection to coupling wavelengths numerically,and show that besides the indexes changes due to photoelastic effect,axial strain′s influence to coupling wavelengths is also realized by the variations of core and cladding′s radii and especially the grating′s period.By comparing and analysing,the reason for difference and identity of orders of magnitude of responsivities of long-perild fiber gratings and fiber Bragg gratings to temperature and strain respectively is found out.