Abstract:
This study introduces a innovative multi-layered photonic crystal fiber (PCF) featuring a pair of distinct and independent directed mode regions, collectively supporting a total of 112 orbital angular momentum (OAM) modes, comprising 76 + 36 modes. The designed nested PCF is characterized by a prominent primary channel, incorporating a pair of ring areas with high refractiveindex composed of Borosilicate glass (SF6), surrounded by a cladding with fused silica as the background material. The findings indicate wherein the suggested PCF exhibits a adequately substantial effective refractive index difference (ERID), along with a consistently flat dispersion profile, expansive effective mode field area and minimal confinement loss across the wavelength range of 0.6 to 1 μm. The confinement loss (CL) ranges approximately between 2.49701 × 10−11 to 9.13425 × 10 −9 dB/m, while highest attained OAM purity is 99.31969% and 98.99258% at HE2,1 mode respectively for both inner and outer rings. All the modes demonstrate ERIDs exceeding 10 −4, and minimum dispersion variation observed is −856 ps/km − nm. Additionally, achieving an outstanding isolation performance, with the highest attained ISO reaching 294 dB at HE9,1 mode and observed a substantial effective mode area of 9.15 μm2 and 25.8 μm2 respectively for inner and outer rings. This research leverages COMSOL Multiphysics' finite element method (FEM) and perfectly matched layer (PML) capabilities alongside MATLAB processing to calculate all key variables of the offered fiber. Therefore, the suggested Photonic PCF demonstrates promising prospects for extended-range, high-capacity data transmission within optical communications and applications related to OAM sensing.
