一种高双折射低损耗大负色散光子晶体光纤的设计

Design of Photonic Crystal Fiber with High Birefringence, Low Confinement Loss and Large Negative Dispersion

摘要:

设计了一种新型光子晶体光纤结构,该光纤包层包含六个由不同形状空气孔组成的轴对称的三角晶格,并在中间沿x轴引入一排大小不同的椭圆空气孔,实现了高双折射、低限制性损耗和大负色散特性。构建了该光子晶体光纤的有限元模型,基于该模型研究了中心两个空气孔的偏转角对LP₀₁模和LP₁₁模的模场分布、双折射系数、限制性损耗和色散系数的影响。研究表明,在偏转角α=90°时该型光纤具有最优性能,即LP₀₁模可在波长为1550nm处获得高达3.618×10-2的双折射、仅为1.999×10-14dB/m的限制性损耗以及低至-764ps/(nm·km)的大负色散,其综合传输特性优于现有典型光子晶体光纤。

Abstract:

A new type of photonic crystal fiber structure is designed in this paper. The fiber cladding contains six axisymmetric triangular lattices composed of air holes with different shapes, and a row of elliptical air holes with different sizes were introduced along the x-axis in the middle to achieve high birefringence, ultra-low confinement loss and large negative dispersion. The model of the photonic crystal fiber was constructed by the finite element method, based on which, the effects of the rotation angle of the two central air holes on the mode field distribution, birefringence coefficient, confinement loss and dispersion coefficient of the LP₀₁ mode and LP₁₁ mode were studied. The results show that the fiber has the optimal performance when the rotation angle α=90°, that is, at the wavelength of 1550nm, the LP₀₁ mode can obtain the birefringence, confinement loss and dispersion as 3.618×10-2, 1.999×10-14dB/m and -764ps/(nm·km), respectively.