Design of a broadband dispersion compensated ultra-high nonlinear photonic crystal fiber

Abstract

A photonic crystal fiber (PCF) with four circular rings of air holes expanded toward the cladding region is proposed. Four circular tiny air hole rings have been used between the air holes in a regular circular PCF to achieve low dispersion and confinement loss. Additionally, the core region is perforated with a rectangular-shaped hole filled with an extremely nonlinear material, gallium phosphide, to achieve the desired level of nonlinearity. We achieved extremely high nonlinearity and birefringence values of 4.6104 W−1 km−1 and 0.078 at the 1.55 µm telecommunication window by doing so. Further, we observed the structure with varying pitch (Ʌ) values and found a significant reduction in dispersion and confinement loss, as well as a decrease in effective material loss. Thus, at 1.55 µm, an ultra-high negative dispersion of − 8000 ps/nm km is achieved, particularly with Ʌ = 1.8 µm, along with extremely low confinement and material losses of 10–9 dB/km and 0.017 cm−1, respectively. Similarly, other critical parameters such as the power fraction, numerical aperture, and effective area have been examined. Hence, owing to these enhanced optical properties, the proposed PCF is capable of effectively compensating for dispersion, generating supercontinuum, and maintaining polarization.