模间色散为零的双芯光子晶体光纤

设计一种在短波长处可以实现零模间色散的双芯光子晶体光纤,该光纤的包层气孔直径具有渐变结构。利用全矢量有限元法进行分析,得到光纤耦合系数、模间色散及走离距离特性随传输频率和结构参数的变化曲线。数值分析结果表明,可以通过调节双芯间小孔的直径,灵活控制耦合系数的变化。在特定的传输频率处,模间色散存在过零点。且双芯间小孔的直径越大,模间色散过零点所在的传输频率越低。当模间色散为零时,可以完全消除模式间相位不匹配导致的脉冲失真,从而实现能量的完全交换。

Dual-core photonic crystal fiber with zero inter-modal dispersion

A kind of dual-core photonic crystal fiber with zero inter-modal dispersion was designed,in which the air holes with different size were gradually arranged in the cladding.By using the full vector finite element method,the coupling coefficient,the inter-modal dispersion and the walk-off length as a function of transmission frequency and design parameters were investigated.Theoretical results show that the coupling coefficient can be changed easily by adjusting the diameter of the small air hole between the two cores.Especially,the zero inter-modal dispersion can be achieved at a particular frequency.What′s more,the transmission frequency of the zero inter-modal dispersion will decrease for a larger air hole diameter between the two cores.This implies that the pulse distortion effect due to the mismatch between different modes can be eradicated and the 100% power transfer can be realized in such a dual-core photonic crystal fiber at the particular frequency.