title: Generation and transmission of 85.4 Gb/s real-time 16QAM coherent optical OFDM signals over 400 km SSMF with preamble-less reception.
abstract: This paper presents a real-time, coherent optical OFDM transmitter based on a field programmable gate array implementation. The transmitter uses 16QAM mapping and runs at 28 GSa/s achieving a data rate of 85.4 Gb/s on a single polarization. A cyclic prefix of 25% of the symbol duration is added enabling dispersion-tolerant transmission over up to 400 km of SSMF. This is the first transmission experiment performed with a real-time OFDM transmitter running at data rates higher than 40 Gb/s. A key aspect of the paper is the introduction of a novel method for OFDM symbol synchronization without relying on training symbols. Unlike conventional preamble-based synchronization methods which perform cross-correlations at regular time intervals and let the system run freely in between, the proposed method performs synchronization in a continuous manner ensuring correct symbol alignment at all times.
authors.affiliation: Optical Networks Group, Department of Electronic and Electrical Engineering, (UCL) University College London, Torrington Place, London, WC1E 7JE, UK. r.bouziane@ee.ucl.ac.uk
authors.forename: Rachid
authors.initials: R
authors.lastname: Bouziane
authors.forename: Rene
authors.initials: R
authors.lastname: Schmogrow
authors.forename: D
authors.initials: D
authors.lastname: Hillerkuss
authors.forename: P A
authors.initials: PA
authors.lastname: Milder
authors.forename: C
authors.initials: C
authors.lastname: Koos
authors.forename: W
authors.initials: W
authors.lastname: Freude
authors.forename: J
authors.initials: J
authors.lastname: Leuthold
authors.forename: P
authors.initials: P
authors.lastname: Bayvel
authors.forename: R I
authors.initials: RI
authors.lastname: Killey