title: Free-space optical communications using orbital-angular-momentum multiplexing combined with MIMO-based spatial multiplexing.
abstract: We explore the potential of combining the advantages of multiple-input multiple-output (MIMO)-based spatial multiplexing with those of orbital angular momentum (OAM) multiplexing to increase the capacity of free-space optical (FSO) communications. We experimentally demonstrate an 80 Gbit/s FSO system with a 2×2 aperture architecture, in which each transmitter aperture contains two multiplexed data-carrying OAM modes. Inter-channel crosstalk effects are minimized by the OAM beams' inherent orthogonality and by the use of 4×4 MIMO signal processing. Our experimental results show that the bit-error rates can reach below the forward error correction limit of 3.8×10(-3) and the power penalties are less than 3.6 dB for all channels after MIMO processing. This indicates that OAM and MIMO-based spatial multiplexing could be simultaneously utilized, thereby providing the potential to enhance system performance.
authors.forename: Yongxiong
authors.initials: Y
authors.lastname: Ren
authors.forename: Zhe
authors.initials: Z
authors.lastname: Wang
authors.forename: Guodong
authors.initials: G
authors.lastname: Xie
authors.forename: Long
authors.initials: L
authors.lastname: Li
authors.forename: Yinwen
authors.initials: Y
authors.lastname: Cao
authors.forename: Cong
authors.initials: C
authors.lastname: Liu
authors.forename: Peicheng
authors.initials: P
authors.lastname: Liao
authors.forename: Yan
authors.initials: Y
authors.lastname: Yan
authors.forename: Nisar
authors.initials: N
authors.lastname: Ahmed
authors.forename: Zhe
authors.initials: Z
authors.lastname: Zhao
authors.forename: Asher
authors.initials: A
authors.lastname: Willner
authors.forename: Nima
authors.initials: N
authors.lastname: Ashrafi
authors.forename: Solyman
authors.initials: S
authors.lastname: Ashrafi
authors.forename: Roger D
authors.initials: RD
authors.lastname: Linquist
authors.forename: Robert
authors.initials: R
authors.lastname: Bock
authors.forename: Moshe
authors.initials: M
authors.lastname: Tur
authors.forename: Andreas F
authors.initials: AF
authors.lastname: Molisch
authors.forename: Alan E
authors.initials: AE
authors.lastname: Willner