Compensation-free high-dimensional free-space optical communication using turbulence-resilient vector beams

Ziyi Zhu,Taylor Winder,Darrick Hay,Molly Janasik,Gerd Leuchs,Alexander Fyffe,Yiyu Zhou,Zhimin Shi,Brian Kantor,Robert W Boyd

doi:10.1038/s41467-021-21793-1

Abstract

Free-space optical communication is a promising means to establish versatile, secure and high-bandwidth communication between mobile nodes for many critical applications. While the spatial modes of light offer a degree of freedom to increase the information capacity of an optical link, atmospheric turbulence can introduce severe distortion to the spatial modes and lead to data degradation. Here, we demonstrate experimentally a vector-beam-based, turbulence-resilient communication protocol, namely spatial polarization differential phase shift keying (SPDPSK), that can reliably transmit high-dimensional information through a turbulent channel without the need of any adaptive optics for beam compensation. In a proof-of-principle experiment with a controllable turbulence cell, we measure a channel capacity of 4.84 bits per pulse using 34 vector modes through a turbulent channel with a scintillation index of 1.09, and 4.02 bits per pulse using 18 vector modes through even stronger turbulence corresponding to a scintillation index of 1.54.

Highlights

Free-space optical communication is a promising means to establish versatile, secure and high-bandwidth communication between mobile nodes for many critical applications
We propose a new high-dimensional communication protocol, namely, spatial polarization differential phase shift keying (SPDPSK), that encodes and decodes highdimensional information based on orthogonal spatial polarization states of a family of vector vortex beams
We consider a family of vector vortex beams, each formed by superposing two Laguerre–Gaussian (LG) beams that possess orbital angular momentum (OAM) charges of opposite signs in the two circular polarization bases

Summary

Introduction

Free-space optical communication is a promising means to establish versatile, secure and high-bandwidth communication between mobile nodes for many critical applications. We here propose to use a family of vector vortex beams with orthogonal spatial polarization profiles to represent a large number of information levels.

Results

Conclusion