【摘要】 从理论和实验两个方面分析了长周期光纤光栅(LPFG)前3阶包层模的透射谱特性与光栅外包层厚度间的关系。LPFG的谐振波长漂移范围随着其外包层厚度的减小而扩大,同时,高阶耦合模LP04模的谐振波长漂移强于低阶模。研究表明,通过设计光纤光栅结构能改善其各阶包层模谐振峰对环境折射率的灵敏度。更多还原

【Abstract】 The relation between the transmission spectrums of the first three orders of cladding mode and the outer cladding thickness of the LPFG is analyzed theoretically and experimentally.The resonance wavelength shift of LPFG is increased with the reduction of the outer cladding thickness,in the same time,the resonance wavelength shift of higher order coupling mode,LP₀₄ mode,is stronger than that of lower order modes.The research shows certain LPFG structure can improve the sensitivity of the resonance peaks of cladding modes on ambient refractive index.更多还原