Design of a novel specialty structure fiber for orbital angular momentum multiplexing in optical communications

Abstract Based on the anti-resonance principle and photonic crystal structure, we established a fiber model for orbital angular momentum (OAM) mode transmission, and simulated the transmission of OAM mode in the specialty fiber. The simulation result indicates that the first-order radial modes can be effectively transmitted by adjusting the thickness and radius of the high refractive index ring layer. Meanwhile, by optimizing the size and number of external nested anti-resonant rings, the confinement loss (CL) of the modes can be reduced to less than 10 −8 dB·m −1 . On the basis of these structural designs, we make additional optimization of the high refractive index ring layer, and the fiber can achieve low CL, and high mode quality of 62 OAM modes at C + L waveband. The results of this research can provide theoretical reference and engineering guidance for the structural design of optical fiber for optical communication.