宽带色散平坦光子晶体光纤的优化设计与特性分析

Modified Design and Characteristics Analysis of Broadband Flat Dispersion Photonic Crystal Fiber

设计了一种第一层为椭圆空气孔缺陷的宽带色散平坦光子晶体光纤,借助全矢量有限元法对这种结构的光子晶体光纤的色散特性、模场面积、双折射和限制损耗特性进行了数值模拟。结果表明改进的光子晶体光纤的色散曲线可以在很宽的波长范围内保持色散平坦并具有较低的色散值,其模场面积较未改进光子晶体光纤的模场面积要大,光纤的限制损耗变小且双折射也相当小。主要分析了这种光纤的结构参数的优化后,光纤的色散特性、有效模面积、双折射以及限制损耗特性的变化规律,最终设计了在1200～1800 nm波长范围内超平坦色散的光子晶体光纤。

An optimized design of flat dispersion photonic crystal fiber is presented.The circular air holes of the first central ring are replaced by elliptic air holes.Based on full vectorial model,the finite element method is adopted to analyze the characteristics of photonic crystal fiber such as dispersion properties,modal area,birefringence and confinement loss.The simulation results show that this photonic crystal fiber has flat dispersion curve over a wide band,and its dispersion value is close to zero.The mode area of this photonic crystal fiber is comparatively big,the loss of this photonic crystal fiber is low, and its birefringence is negligible. With choosing suitable structure parameters, a flat dispersion photonic crystal fiber ranging from 1 200 nm to 1 800 nm can be designed.