title: Modulator-free quadrature amplitude modulation signal synthesis.
abstract: The ability to generate high-speed on-off-keyed telecommunication signals by directly modulating a semiconductor laser's drive current was one of the most exciting prospective applications of the nascent field of laser technology throughout the 1960s. Three decades of progress led to the commercialization of 2.5 Gbit s(-1)-per-channel submarine fibre optic systems that drove the growth of the internet as a global phenomenon. However, the detrimental frequency chirp associated with direct modulation forced industry to use external electro-optic modulators to deliver the next generation of on-off-keyed 10 Gbit s(-1) systems and is absolutely prohibitive for today's (>)100 Gbit s(-1) coherent systems, which use complex modulation formats (for example, quadrature amplitude modulation). Here we use optical injection locking of directly modulated semiconductor lasers to generate complex modulation format signals showing distinct advantages over current and other currently researched solutions.
authors.affiliation: Optoelectronics Research Centre, University of Southampton, Southampton SO17 1BJ, UK.
authors.forename: Zhixin
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Bell Labs, Alcatel-Lucent, Holmdel, New Jersey 07733, USA.
authors.forename: Joseph
authors.initials: J
authors.lastname: Kakande
authors.affiliation: Eblana Photonics Inc., Unit 31, Pearse Street, Dublin 2, Ireland.
authors.forename: Brian
authors.initials: B
authors.lastname: Kelly
authors.affiliation: Eblana Photonics Inc., Unit 31, Pearse Street, Dublin 2, Ireland.
authors.forename: John
authors.initials: J
authors.lastname: O'Carroll
authors.affiliation: Eblana Photonics Inc., Unit 31, Pearse Street, Dublin 2, Ireland.
authors.forename: Richard
authors.initials: R
authors.lastname: Phelan
authors.affiliation: Optoelectronics Research Centre, University of Southampton, Southampton SO17 1BJ, UK.
authors.forename: David J
authors.initials: DJ
authors.lastname: Richardson
authors.affiliation: Optoelectronics Research Centre, University of Southampton, Southampton SO17 1BJ, UK.
authors.forename: Radan
authors.initials: R
authors.lastname: Slavík