光缆内相互影响的理论研究总地说还未达到应用于工程计算的程度。但是,要正确评价光缆的电气特性及其结构的最佳设计,必须获得光缆内光纤之间的串音干扰及其对相互影响防卫度的数据。试分析一种直线均匀的由纤芯与包层组成的双层光纤,纤芯的折射率是n_1,包层的折射率是n_2。折射率较小(n_2>n_1)的包层的作用是在它与纤芯的界面上造成多次反射的最佳条件,以 Theoretical studies of the mutual influence in optical fiber cables have not yet reached the level of engineering calculation. However, to properly evaluate the electrical characteristics of an optical cable and the optimal design of its structure, it is necessary to obtain crosstalk interference between the optical fibers within the optical cable and their effect on the mutual defense. This paper analyzes a kind of double-layer fiber with straight line and consisted of core and cladding. The refractive index of the core is n_1 and the refractive index of the cladding is n_2. The role of the cladding with a smaller refractive index (n_2> n_1) is to create the optimal conditions for multiple reflections at its interface with the core to