A Novel Ultra-high Birefringent Photonic Crystal Fiber for Nonlinear Applications

In this paper, a novel polarization-maintaining highly birefringent photonic crystal fiber (PMHB-PCF) has been investigated by using finite element method (FEM). Initially, the numerical analysis is carried out to ascertain its PMHB characteristics by using two different novel PCF structures (hexagonal-elliptical PCF and elliptical-elliptical PCF) and their performance characteristics are measured. By inducing the asymmetries in the fiber structure, the beat length of the fiber and their modal birefringence have been optimized. In proposed designs hexagonal-elliptical (cladding layers) PCF structure provides an ultra-high birefringence of about 4.51 × 10–2 with a lower beat length of 34.37 µm. This reported fiber exposed a high nonlinear coefficient of about 61. 95 W−1 km−1 at the operating wavelength of 1.55 µm. Also, it has a normalized frequency parameter (V parameter) of about 1.373 over the optical spectrum of 1.3 to 1.6 µm; it ensures the fiber single-mode operation. Due to the high nonlinearity and birefringence, this fiber is more suitable for nonlinear applications. It confirms the phase-matching conditions for the purpose like wavelength conversion which employs four-wave mixing technique.