title: Experimental demonstration of 20 Gbit/s data encoding and 2 ns channel hopping using orbital angular momentum modes.
abstract: We explore the use of the spatial domain as a degree of freedom for data encoding and channel hopping. We experimentally demonstrate data encoding at 20  Gbit/s using four possible orbital angular momentum (OAM) modes. The influence of mode spacing and time misalignment between modal channels on the switching crosstalk and bit-error rates is investigated. We find that the use of adjacent modes with a mode spacing of one introduces an extra power penalty of 3.2 dB compared with a larger mode spacing. Moreover, we demonstrate reconfigurable hopping of a 100  Gbit/s quadrature-phase-shift-keying (QPSK) data channel between four OAM modes with a 2 ns switching guard time. The results show that the power penalties for different hopping rates and mode spacings are less than 5.3 dB.
authors.forename: Asher J
authors.initials: AJ
authors.lastname: Willner
authors.forename: Yongxiong
authors.initials: Y
authors.lastname: Ren
authors.forename: Guodong
authors.initials: G
authors.lastname: Xie
authors.forename: Zhe
authors.initials: Z
authors.lastname: Zhao
authors.forename: Yinwen
authors.initials: Y
authors.lastname: Cao
authors.forename: Long
authors.initials: L
authors.lastname: Li
authors.forename: Nisar
authors.initials: N
authors.lastname: Ahmed
authors.forename: Zhe
authors.initials: Z
authors.lastname: Wang
authors.forename: Yan
authors.initials: Y
authors.lastname: Yan
authors.forename: Peicheng
authors.initials: P
authors.lastname: Liao
authors.forename: Cong
authors.initials: C
authors.lastname: Liu
authors.forename: Mohammad
authors.initials: M
authors.lastname: Mirhosseini
authors.forename: Robert W
authors.initials: RW
authors.lastname: Boyd
authors.forename: Moshe
authors.initials: M
authors.lastname: Tur
authors.forename: Alan E
authors.initials: AE
authors.lastname: Willner