Low Dispersion Photonic Crystal Fiber for OAM Mode

In this paper, we design a new type of photonic crystal fiber (PCF), which can transmit 26 orbital angular momentum modes (OAMs), by inserting a kind of micro-structure to common total internal reflection PCF. Compared with the original PCF for reference, the analysis data of the new type PCF shows a great improvement in term of dispersion property over a bandwidth of 300 nm from 1.5 μm to 1.8 μm. For some high order modes, the dispersion could decrease by 1/4 after the application of the inserted micro-structure. Other mode properties of the new type PCF including effective indices, confinement loss and nonlinear coefficient are also calculated.