A GeO2-doped Silica Ring-core Bragg Fiber for OAM Mode Propagation

Abstract

In this paper, a Bragg fiber is designed and proposed that can support the propagation of orbital angular momentum (OAM) modes. Finite element analysis is employed to obtain modes in the PCF. The PCF is observed to support 12 OAM modes at 1.55 $\mu \mathrm{m}$. Mode purity of OAM modes was calculated in order to facilitate for low loss transmission. We obtained a a high value of 94% for OA$\mathrm{M}_{1,1}$ mode. Other fiber parameters are also calculated. We obtained and observed a zero-dispersion wavelength at approximately 1.77 $\mu$m. Confinement loss in the PCF is also calculated. Effective area is obtained and seen to have a monotonic increase in the wavelength window 0.5 $\mu$m to 2.0 $\mu$m. Further, the calculation of nonlinearity yields a monotonically decreasing graph and shows an inverse nature with effective area as predicted.