title: High-capacity millimetre-wave communications with orbital angular momentum multiplexing.
abstract: One property of electromagnetic waves that has been recently explored is the ability to multiplex multiple beams, such that each beam has a unique helical phase front. The amount of phase front 'twisting' indicates the orbital angular momentum state number, and beams with different orbital angular momentum are orthogonal. Such orbital angular momentum based multiplexing can potentially increase the system capacity and spectral efficiency of millimetre-wave wireless communication links with a single aperture pair by transmitting multiple coaxial data streams. Here we demonstrate a 32-Gbit s(-1) millimetre-wave link over 2.5 metres with a spectral efficiency of ~16 bit s(-1) Hz(-1) using four independent orbital-angular momentum beams on each of two polarizations. All eight orbital angular momentum channels are recovered with bit-error rates below 3.8 × 10(-3). In addition, we demonstrate a millimetre-wave orbital angular momentum mode demultiplexer to demultiplex four orbital angular momentum channels with crosstalk less than -12.5 dB and show an 8-Gbit s(-1) link containing two orbital angular momentum beams on each of two polarizations.
authors.affiliation: 1] Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089, USA [2].
authors.forename: Yan
authors.initials: Y
authors.lastname: Yan
authors.affiliation: 1] Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089, USA [2].
authors.forename: Guodong
authors.initials: G
authors.lastname: Xie
authors.affiliation: 1] School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, UK [2].
authors.forename: Martin P J
authors.initials: MP
authors.lastname: Lavery
authors.affiliation: 1] Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089, USA [2].
authors.forename: Hao
authors.initials: H
authors.lastname: Huang
authors.affiliation: Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089, USA.
authors.forename: Nisar
authors.initials: N
authors.lastname: Ahmed
authors.affiliation: Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089, USA.
authors.forename: Changjing
authors.initials: C
authors.lastname: Bao
authors.affiliation: Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089, USA.
authors.forename: Yongxiong
authors.initials: Y
authors.lastname: Ren
authors.affiliation: Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089, USA.
authors.forename: Yinwen
authors.initials: Y
authors.lastname: Cao
authors.affiliation: Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089, USA.
authors.forename: Long
authors.initials: L
authors.lastname: Li
authors.affiliation: Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089, USA.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Zhao
authors.affiliation: Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089, USA.
authors.forename: Andreas F
authors.initials: AF
authors.lastname: Molisch
authors.affiliation: School of Electrical Engineering, Tel Aviv University, Ramat Aviv 69978, Israel.
authors.forename: Moshe
authors.initials: M
authors.lastname: Tur
authors.affiliation: School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, UK.
authors.forename: Miles J
authors.initials: MJ
authors.lastname: Padgett
authors.affiliation: Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089, USA.
authors.forename: Alan E
authors.initials: AE
authors.lastname: Willner