Highly nonlinear with low confinement losses square photonic crystal fiber based on a four-hole unit

Abstract

A novel simple structure of a highly nonlinear square photonic crystal fiber with low confinement losses is proposed. The simulation results show that a nonlinear coefficient of 83.3W−1km−1 and a low confinement loss of less than 10−9dB/m at the wavelength of 1.55μm, and the corresponding effective mode area is about 1.46μm2 by introducing the unique four-hole unit structure in the cladding region. The proposed PCF is expected to be useful for super-continuum generation, nonlinear optics and optical communication systems.