Highly nonlinear polarization-maintaining photonic crystal fiber with nanoscale GaP strips

A highly birefringent silica photonic crystal fiber (PCF) is proposed with nanoscale gallium phosphide strips at the core and modified spiral cladding air hole distribution. Optical properties of the PCF are simulated using the finite element method. Significant influences of low-refractive-index slot region confinement and high-index strips confinement are observed for two different modes. This introduces a high birefringence of ∼0.58 at 1.55 μm wavelength. Moreover, a high nonlinearity coefficient of the order of ∼10⁴  W^-1  km^-1 is achieved in the wavelength range from 1.4 to 1.7 μm. The proposed fiber will find promising applications in coherent optical communications and sensing applications.