【摘要】 以光纤三层模型为基础,详细介绍了长周期光纤光栅理论最新研究动态,给出了对正弦和矩形两种折射率调制型的长周期光纤光栅的性能及其在均匀和非均匀两种情况下其传输谱的各种最新求解过程及方法;在求解包层模色散方程得到各阶包层模式的传播常数的基础上,对均匀折射率调制型光栅的耦合系数、谐振波长透射系数和透射谱带宽的相关理论进行分析;对于非均匀光栅,介绍了传输矩阵法分析方法,给出了长周期光纤光栅辐射模的最新研究结果。更多还原

【Abstract】 Based on the three-layer mode of Long Period Fiber Gratings(LPFGs),the properties of LPFGs with sinusoidal and rectangular index modulations are discussed.The procedures,methods,and latest research of solving the transmission spectra with the even and uneven modulations has been described in detail.On the base of solving the dispersion equations of the cladding mode and obtaining the propagation constants of the cladding modes, the LPFGs with mean index modulation is analyzed.The coupling coefficient,the transmission coefficient at resonant wavelength and the transmission spectrum are also analyzed.The fundamental matrix approach used to analyze the LPFGs with uneven refractive index modulation is introduced.Finally,the issues concerning the radiation modes are discussed.It’s importance for the LPG’s fabrication,encapsulation,and reverse designing of the spectrum.更多还原