负折射率及零折射率光纤的光学特性

研究了芯层折射率为正，包层折射率为负的光纤导模光学特性，通过色散曲线分析比较了与常规光纤的不同，表现为低阶的简并的模式更少，单模存在的区域更多。进而分析了当包层折射率趋于零时的光学特性，发现与前两种光纤的光学特性都不同。分析发现当包层的介电常数和磁导率有一个为零时，在较小的区域各自出现了一条单模，与常规光纤的HE11模特性有很大不同，其色散曲线偏离方式与常规光纤相反，且出现了无模式存在的区域。

Optical characteristics of fibers with negative refractive and zero refractive index

The optical characteristics of guided modes in a fiber formed by a core with usual refractive index and a negative refractive index cladding are studied, the difference compared with normal fiber is analyzed through the dispersion curves showing less degenerate modes and larger single-mode area.When the cladding refractive index tends to zero ,the optical characteristics are different from the former two fibers. A single-mode in the smaller region V is found ,when the permittivity or permeability of the cladding is zero.It is quite different from the mode HE11 in a normal fiber, its dispersive curve has an opposite tendency, and there are some areas where no modes could exist .