Mode-group selective photonic lanterns for multiplexing multi-order orbital angular momentum modes.

Abstract

The lack of research on photonic lanterns multiplexing multi-order orbital angular momentum (OAM) modes hinders the development of OAM space division multiplexing systems. In this paper, an annular multicore photonic lantern (AMCPL) for multiplexing several OAM mode groups is proposed and demonstrated. Comprehensive simulations are carried out to investigate the effect of the multicore arrangements on the crosstalk (XT) between different OAM mode groups. Further optimization provides an inverted multicore arrangement of the OAM AMCPL with balanced XT between high-order OAM mode groups with topological charges |l| = 2 to 5 for the first time, of which the highest XT between target mode groups does not exceed -27.20 dB at wavelengths from 1300 nm to 1600 nm, and mode conversion efficiencies of all target mode groups exceed 99.5%. Furthermore, a quantum interpretation is given to reveal the characteristics of the evolution of the supermodes along the taper of the OAM AMCPL, which has not been reported.