中文摘要：

对中心凹陷W型光纤严格按照矢量法,利用光场的电磁边界连续条件建立解析模型得到特征方程,通过数值计算分析了凹陷深度和宽度对中心凹陷W型光纤的基膜HE11和高次模TE01截止波长、单模工作区间和基膜能量损耗的影响,并与相同结构参数的W型光纤进行了比较。

英文摘要：

In this paper,W-type fibers with a central index dip are studied.Based on strict vector methods,an analytical model is built by continuity conditions of electromagnetic field and the characteristic equation is obtained.According to numerical calculation,effects of central index dip on the cutoff wavelength,operating range of single mode and energy loss of the fundamental mode are studied.The related result is compared to the standard W-type fiber which has the same parameters.