High-order orbital angular momentum mode generator based on twisted photonic crystal fiber

Opt Lett. 2018 Apr 15;43(8):1786-1789. doi: 10.1364/OL.43.001786.

Abstract

High-order orbital angular momentum (OAM) modes, namely, OAM+5 and OAM+6, were generated and demonstrated experimentally by twisting a solid-core hexagonal photonic crystal fiber (PCF) during hydrogen-oxygen flame heating. Leaky orbital resonances in the cladding depend strongly on the twist rate and length of the helical PCF. Moreover, the generated high-order OAM mode could be a polarized mode. The secret of the successful observation of high-order modes is that leaky orbital resonances in the twisted PCF cladding have a high coupling efficiency of more than -20 dB.