Abstract

The performance of LDPC-precoded, orbital-angular-momentum (OAM) modulation is studied over a 1-km free-space laser communication link subject to OAM modal crosstalk induced by atmospheric turbulence. The multidimensional signal constellation is designed as the Cartesian product of a one-dimensional non-negative pulse-amplitude modulation and a set of orthogonal OAM modes. We evaluate the performance of this modulation scheme by first determining conditional probability density functions (PDFs) of the modal crosstalk for each symbol, resulting from the propagation in weak turbulence using a numerical propagation model. It is observed that OAM modulation is more sensitive to atmospheric turbulence as the number of dimensions increases. However, this can be efficiently mitigated by an error-correction code. The coded OAM modulation scheme provides an energy-efficient alternative to single-mode transmission, since a larger rate can be obtained per given bandwidth.

© 2012 IEEE

LDPC-coded orbital angular momentum (OAM) modulation for free-space optical communication

Ivan B. Djordjevic and Murat Arabaci
Opt. Express 18(24) 24722-24728 (2010)

Deep-space and near-Earth optical communications by coded orbital angular momentum (OAM) modulation

Ivan B. Djordjevic
Opt. Express 19(15) 14277-14289 (2011)

Performance analysis of a LDPC coded OAM-based UCA FSO system exploring linear equalization with channel estimation over atmospheric turbulence

Yan Zhang, Ping Wang, Tao Liu, Lixin Guo, Yutao Li, and Wei Wang
Opt. Express 26(17) 22182-22196 (2018)

Turbulence-induced channel crosstalk in an orbital angular momentum-multiplexed free-space optical link

Jaime A. Anguita, Mark A. Neifeld, and Bane V. Vasic
Appl. Opt. 47(13) 2414-2429 (2008)

Two-stage cross-talk mitigation in an orbital-angular-momentum-based free-space optical communication system

Zhen Qu and Ivan B. Djordjevic
Opt. Lett. 42(16) 3125-3128 (2017)