A new birefringence controlling technique using varying index profile core of photonic crystal fiber

In this paper, we present a birefringence controlling technique with varying the index profile (alpha) of the graded core photonic crystal fiber (GC-PCF). This GC-PCF is composed of cladding with circular and elliptical air holes arranged in isosceles triangular lattice. Elliptical air holes are located only in the first inner ring. The finite difference time domain (FDTD) with transparent boundary condition (TBC) is used to analyze such PCF. Numerical investigation demonstrate that by varying the index profile (α) and diameter of the core region (Cd), the birefringence is up to 8.28 × 10−3 at the excitation wavelength of λ = 1.55 μm.