Error-rate Floors in Differential n-level Phase-shift-keying Coherent Receivers employing Electronic Dispersion Equalisation

Abstract

(2011) Error-rate floors in differential n-level phase-shift-keying coherent receivers employing electronic dispersion equalisation. Journal of Optical Communications,. Permanent WRAP URL:http://wrap.warwick.ac.uk/93887 Copyright and reuse:The Warwick Research Archive Portal (WRAP) makes this work by researchers of the University of Warwick available open access under the following conditions. Copyright © and all moral rights to the version of the paper presented here belong to the individual author(s) and/or other copyright owners. To the extent reasonable and practicable the material made available in WRAP has been checked for eligibility before being made available.Copies of full items can be used for personal research or study, educational, or not-for-profit purposes without prior permission or charge. Provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. Publisher's statement:"The final publication is available at www.degruyter.com ". : http://dx.doi.org/10.1515/JOC.2011.031 A note on versions:The version presented here may differ from the published version or, version of record, if you wish to cite this item you are advised to consult the publisher's version. Please see the 'permanent WRAP URL' above for details on accessing the published version and note that access may require a subscription. Introduction: Coherent optical communications research activities focuses currently on achieving system bit-rates of 100 -1000 Gb/s and to apply electronic dispersion equalization to account for several thousand kilometers of transmission [1,2]. Practical high capacity system configurations have been polarization multiplexed n-level phase shift keying (nPSK) and quadrature amplitude modulation (nQAM) systems (n = 4, 8, 16, 32, 64,…) with differential detection. The demodulation in the receiver is coherent (with an optical transmitter (Tx) and local oscillator (LO) laser) and effectively homodyne since homodyne detection provides the closest possible channel stacking in wavelength division multiplexed (WDM) system implementations as well as the best system sensitivity. Phase noise becomes a prime system design parameter for high-constellation coherent systems since it affects the electronic carrier phase extraction [3,4] and furthermore the LO phase noise influence is enhanced by electronic dispersion compensation [5]. It is possible (and straightforward) to extend the analytical derivation for the enhanced LO phase noise in [5] to specify the BER floor for nPSK and 2nQAM systemswith and without practical n-power carrier phase extraction by generalizing results from [3,4]. In [6] a similar study including the Viterbi-Viterbi carrier phase extraction has been presented. The purpose of our paper is to provide practically important

Digital Signal Processing for Optical Communications and Networks

“…Coherent optical detection re-attracted the research interests until 2005, since the advanced modulation formats i.e. m-level phase shift keying (m-PSK) and m-level quadrature amplitude modulation (m-QAM) can be applied [27][28][29][30]. In addition, coherent optical detection allows the electrical mitigation of system impairments.…”

Digital Adaptive Carrier Phase Estimation in Multi-level Phase Shift Keying Coherent Optical Communication Systems

“…With the full capture of the amplitude and the phase of optical signals, coherent optical detection and digital signal processing (DSP) allow the powerful equalization and mitigation of the communication system impairments in the electrical domain, and thus have become one of the most promising techniques for the next-generation optical fiber transmission networks . Recently, some feed-forward and feed-back carrier phase estimation (CPE) algorithms have been proposed to compensate the phase noise from the laser sources [22][23][24][25][26][27][28][29][30][31][32][33][34]. Among these reported carrier phase estimation methods, the one-tap normalized least-mean-square (LMS) algorithm has been validated for compensating the laser phase noise effectively in the high speed coherent optical transmission systems [24][25][26].…”