Dual-guided-mode-region circular photonic crystal fiber with low nonlinear coefficients and flat dispersion for transmission of orbital angular momentum modes

Abstract

As a new degree of freedom in optical fiber communication, the transmission of orbital angular momentum (OAM) modes has attracted extensive attention in recent years. Herein, a photonic crystal fiber with a dual-guided mode field was designed for the transmission of OAM modes in the wavelength range between 1.50 and 1.60 μm. The effective index difference, dispersion, nonlinear coefficient, and isolation parameters were analyzed systematically by the finite element method. The results showed that the effective index difference of all OAM modes was greater than 1 × 10 − 4, the nonlinear coefficient was as low as 0.492 km − 1 · W − 1, and dispersion was very flat with a minimum variation of 4.033 ps / ( km · nm ) . The fiber with outstanding properties has great potential and provides insights into how to improve the efficiency of optical communication.