锥形光子晶体光纤的基模特性分析

本文研究了锥形光子晶体光纤(TPCF)的基模演化特性,分析了包层空气填充率对其特性的影响.数值计算结果表明TPCF比常规锥形光纤更能束缚模场;在相同的拉锥条件下,包层空气填充率越大的TPCF,其模场能保持芯模的形式传输更长的距离并且其芯区能量密度也越大.而TPCF的有效面积沿锥体纵向先缓慢减小,后急剧增大,最后又减小,随着空气填充率的增大,有效面积的最大值逐渐向锥尾方向移动.同时,对色散研究表明,在整个锥体中,色散值先负向增大,后正向增大;在空气填充率较小时,其色散曲线沿锥体纵向变化平缓,而空气填充率较大时,色散曲线起伏明显;并且随着空气填充率的减小,色散曲线的最低点移向初始拉锥端.

Fundamental mode characteristics in tapered photonic crystal fiber

Based on the fully vectorial effective index approach and the finite difference method,the fundamental mode characteristics in the tapered photonic crystal fiber(TPCF)are analyzed and compared with conventional tapered fiber.The numerical results show that the TPCF can provide stronger mode confinement than conventional tapered fiber.In the same tapering manner,the core mode can prapagate in smaller diameter in high air-filling fraction TPCF,while in this di- ameter the propagation mode transfers from the core mode to the cladding mode in low air-filling fraction TPCE.Furthermore,the variations of effective area,en- ergy density and the dispersion properties of TPCF with different air filling fractions and different positions in taper are investigated respectively.