Demonstration of km-scale orbital angular momentum multiplexing transmission using 4-level pulse-amplitude modulation signals

Abstract

By designing and fabricating two kinds of orbital angular momentum (OAM) fibers, we demonstrate two OAM modes (OAM₊₁ and OAM_-1) multiplexing transmission and demultiplexing in OAM fiber links. Moreover, we also experimentally demonstrate 4-level pulse-amplitude modulation (PAM-4) signal transmission using two OAM modes multiplexing in a km-scale OAM fiber and achieve a bit-error rate (BER) below 2×10^-3 without multiple-input-multiple-output (MIMO) digital signal processing (DSP). The obtained results with favorable data-carrying OAM multiplexing transmission performance show potential application in km-scale short-reach optical interconnects.