A new technique to optimize the properties of photonic crystal fibers supporting transmission of multiple orbital angular momentum modes

Spurred by the continuous development of orbital angular momentum (OAM) optical fiber communication technology, many photonic crystal fibers (PCFs) with excellent properties have been proposed. However, design and optimization of the performance of PCFs are usually complex. In this paper, a new optimization method is described and demonstrated on a LaSF09 high refractive index ring with a certain thickness inlaid in the central pore. The effective index difference, dispersion, effective mode area, nonlinear coefficient, numerical aperture (NA), OAM purity, walk-off length, and confinement loss at 1.55 mu m are analyzed. A conventional photonic crystal fiber (PCF) that can transmit OAM modes is used to verify the method and our results reveal the validity and large potential of the method pertaining to the design and optimization of PCFs.