title: Digital coherent superposition for performance improvement of spatially multiplexed coherent optical OFDM superchannels.
abstract: We demonstrate the use of digital coherent superposition to improve the performance of space-division-multiplexed (SDM) 676-Gb/s OFDM-16QAM superchannels, achieving ~4 dB improvement in OSNR by using two SDM copies and 1075-km (14 x 76.8 km) transmission over a seven-core-fiber with an effective aggregate spectral efficiency of 23.7 b/s/Hz. We further show that the performance improvement from the coherent superposition is retained in the nonlinear transmission regime through coordinated scrambling of signal constellations at the transmitter and appropriate unscrambling at the receiver, by using a series of simple scrambling functions.
authors.affiliation: Bell Labs, Alcatel-Lucent, 791 Holmdel-Keyport Road, Holmdel, New Jersey 07733, USA. xiang.liu@alcatel-lucent.com
authors.forename: Xiang
authors.initials: X
authors.lastname: Liu
authors.forename: S
authors.initials: S
authors.lastname: Chandrasekhar
authors.forename: A H
authors.initials: AH
authors.lastname: Gnauck
authors.forename: P J
authors.initials: PJ
authors.lastname: Winzer
authors.forename: S
authors.initials: S
authors.lastname: Randel
authors.forename: S
authors.initials: S
authors.lastname: Corteselli
authors.forename: A R
authors.initials: AR
authors.lastname: Chraplyvy
authors.forename: R W
authors.initials: RW
authors.lastname: Tkach
authors.forename: B
authors.initials: B
authors.lastname: Zhu
authors.forename: T F
authors.initials: TF
authors.lastname: Taunay
authors.forename: M
authors.initials: M
authors.lastname: Fishteyn