Modal analysis of highly birefringent elliptical core photonic crystal fibers from scalar and vectorial effective index method

摘要

In this paper, we report the highly birefringent elliptical core photonic crystal fibers (EC-PCF). The scalar and vectorial effective index methods are used to obtain the average refractive index of 2D triangular photonic crystal cladding. The first order perturbation technique is used to obtain the birefringence properties of EC-PCF. Birefringence of the EC-PCF obtained, is in the order of 10~(-2), which is 10 times higher than that reported for conventional elliptical core fiber. It is shown narrowing the space between the air holes and enlarging the air-hole size in the cladding of PCF can achieve high birefringence. It is observed that for every design of PCF, an optimum hole-pitch exhibits for which EC-PCF shows high birefringence. Further, the effect of core area on birefringence is also studied and it has been revealed that high birefringence can be obtained for smaller core area of EC-PCF. Both Scalar effective index and Vector effective index method with the perturbation approach are applied to compare the high birefringence of EC-PCF.