摘要
建立了Bragg光纤光栅傅里叶模式耦合理论.在分析光纤光栅的耦合模时,发现了耦合模式的振幅系数间存在傅里叶变换关系.推导了将傅里叶变换和模式耦合融合在一起的Bragg光纤光栅反射谱和透射谱的通用表达式.该理论是用傅里叶变换得到Bragg光纤光栅折射率微扰的空域谱,再对该空域谱进行模式耦合分析计算,从而得到Bragg光纤光栅的光谱特性.根据该理论,仿真分析了Bragg光纤光栅的谱特性,与耦合模理论、直接傅里叶变换法进行了对比分析.结果表明,傅里叶模式耦合理论与传统的耦合模理论及实际Bragg光纤光栅的光谱特性一致,具有简单、清晰、直接、精确和分析效率高的特点,可分析任意轴向折射率微扰分布的Bragg光纤光栅结构.
A novel theory,namely,Fourier mode coupling（FMC） theory for fiber Bragg gratings（FBGs） is proposed in this paper.During analyzing coupled modes of FBGs,the Fourier transform relations among the amplitude coefficients of coupled modes are found for the first time.The general expressions of reflective and transmissive spectra of FBGs are deduced from the combination of Fourier transform with the well-known coupled-mode theory.In the proposed FMC theory,the spectral characteristics of the FBG are achieved by the calculation of coupled modes in the spatial domain spectrum,which is the Fourier transform result of refractive index perturbation in the FBG.The FBG spectrum based on the FMC theory is simulated here,and compared with those obtained from the coupled mode theory and pure Fourier transform.The comparison shows that the FMC theory for and the derived spactra of FBGs are in accordance with the coupled mode theory and the practical spectra of the FBG respectively.The FMC theory has many features,these being simple,clear,direct,accurate and fast,which could be used as a universal tool for fast spectrum analysis of any FBG with an arbitrary distribution of refractive index perturbation along the fiber axis.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2010年第12期8597-8606,共10页
Acta Physica Sinica
关键词
光纤器件
BRAGG光纤光栅
傅里叶模式耦合
光谱特性
fiber-optic component
fiber Bragg grating
Fourier mode coupling
spectral characteristics
