Steering high-order perfect vector beams in coherent laser arrays for suppressive crosstalk optical links

Abstract

Coherent beam combining (CBC) has offered an unparalleled approach in achieving high-capacity and high-bandwidth free-space optical (FSO) communication due to its versatile integration functionality and advanced synthetic ability. However, the existing CBC technologies focus primarily on the phase engineering, where crosstalk between different modes is easily involved, thus leading to nontrivial crosstalk in FSO links based on current coherent laser arrays (CLAs). To address this challenge, we propose an encoding method that enables crosstalk reduction via nonorthogonal polarization multiplexing. This is achieved by leveraging concentrically arranged high-order perfect vector beams (PVBs) via well-designed structure of the CLAs. Moreover, the achievable arbitrary high-order PVBs could strongly support the establishment of high-dimensional encoding paradigm. As a conceptual demonstration, we illustrate information transfer case of “NUDT” with zero bit error rate, indicating that the polarization controlled CLA is advantageous in suppressive crosstalk between multi-channels. Compared to phase coupling appearing in coaxial transmitting vortex beams, the observed PVBs display completely independent stable transmitting paths. Therefore, the manipulation of high-order vector beams within the CLA system is hopefully continuously improving the performances of optical links.