Raman-amplification-assisted twisted light multiplexing transmission over large-core fiber

Abstract

Twisted light-carrying orbital angular momentum (OAM) with a helical phase front and doughnut intensity profile has been widely investigated in fiber-optic communications. To facilitate long-distance OAM mode multiplexing transmission, an efficient OAM (de)multiplexer and a suitable inline OAM amplifier are highly desired. Here, we demonstrate three OAM modes and 22 wavelength channels multiplexing transmission with an OAM distributed Raman amplifier (DRA) over 110-km large-core fiber assisted by a homemade all-fiber OAM (de)multiplexer. To characterize the performance of the OAM DRA, two pump configurations including the first-order bidirectional pumping and second-order backward pumping are proposed and demonstrated. The obtained results indicate the successful implementation of the long-distance OAM mode multiplexing transmission assisted by the DRA and an all-fiber OAM (de)multiplexer with favorable performance. These demonstrations may open up new perspectives for ultra-long-haul capacity scaling fiber-optic communications employing OAM modes.