文中基于耦合模理论和简化的阶跃折射率单模光纤三层模型的包层模理论，提出了长周期光纤光栅的传输谱特性仿真的主要步骤及 matlab程序实现，为长周期光纤光栅的数值仿真提供了一种简便的方法-Text-based coupled mode theory and a simplified three-step-index single-mode fiber cladding mode theory model, proposed long-period fiber grating transmission spectrum characteristics of the main steps and matlab simulation program implementation, as the value of long-period fiber grating Simulation provides an easy way to