双芯复合格点光子晶体光纤的负色散特性

Negative Dispersion Properties of Photonic Crystal Fiber with Dual Core and Composite Lattice

介绍了一种双芯复合格点负色散光子晶体光纤,其包层是由连续电介质纯硅背景上挖出的两种大小不同的空气孔构成,芯区是由掺锗的高折射率的材料构成。为了实现负色散,还移去了包层中的一圈空气孔。采用频域有限差分法对其负色散特性进行分析表明,通过调整空气孔间距和两种空气孔的尺寸,可以得到不同程度的宽带负色散。当内芯半径取0.95μm,孔间距取2.15μm,大空气孔直径取1.9μm,小空气孔直径取1.1μm时,可在1.55μm处实现宽带负色散,其半峰全宽超过了200 nm。这种光纤的包层中空气孔呈六边形分布,空气孔的尺寸均大于1μm,降低了制作的难度。这种光纤可以用于波分复用光纤通信系统中的宽带色散补偿。

A negative dispersion photonic crystal fiber （PCF） with dual core and composite lattice is proposed. The cladding is composed of two different air holes based on pure silica, and the inner core is formed with high effective index material doped with germanium. In order to realize negative dispersion, a ring of air holes in the cladding is removed. Using the finite difference frequency domain algorithm, the negative dispersion properties is analyzed. Results show that broadband negative dispersion with different levels can be achieved by optimizing air-hole pitch and two air-hole diameters. Broadband negative dispersion with full width at half maximum exceeding 200 nm is realized at 1.55 μm wavelength when the radius of the inner core, the air-hole pitch, the diameter of the larger hole and the diameter of the smaller hole is 0.95 μm, 2.15 μm, 1.9 μm, 1.1 μm respectively. To decrease the fabrication difficulty, air holes of more than 1 μm and hexagonal lattice are adopted. So this fiber can be used for broadband dispersion compensation in wavelength-division multiplexing optical fiber communication systems.