Chromatic dispersion compensation in coherent transmission system using digital filters

Popov

et al. 2013

Optics Communications

Self Cite

. (2013) Carrier phase estimation methods in coherent transmission systems influenced by equalization enhanced phase noise. Optics Communications, 293. pp. 54-60. Permanent WRAP URL: http://wrap.warwick.ac.uk/93880 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. 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. ABSTRACTWe present a comparative study on three carrier phase estimation algorithms, including a one-tap normalized least mean square (NLMS) method, a block-average method, and a Viterbi-Viterbi method in the n-level phase shift keying coherent transmission systems considering the equalization enhanced phase noise (EEPN). In these carrier phase estimation methods, the theoretical bit-error-rate floors based on traditional leading-order Taylor expansion are compared to the practical simulation results, and the tolerable total effective linewidths (involving the transmitter, the local oscillator lasers and the EEPN) for a fixed bit-error-rate floor are evaluated with different block size, when the fiber nonlinearities are neglected. The complexity of the three carrier phase estimation methods is also discussed. We find that the carrier phase estimation methods in practical systems should be analyzed based on the simulation results rather than the traditional theoretical predictions, when large EEPN is involved. The one-tap NLMS method can always show an acceptable behavior, while the step size is complicated to optimize. The block-average method is efficient to implement, but it behaves unsatisfactorily when using a large block size. The Viterbi-Viterbi method can show a small improvement compared to the block-average method, while it requires more computational complexity.

Section: Simulation Investigation Of Pdm-qpsk Transmission Systemmentioning

confidence: 99%

Carrier phase estimation methods in coherent transmission systems influenced by equalization enhanced phase noise

Popov

et al. 2013

Optics Communications

Self Cite

“…Depending on the impairment, digital signal processing (DSP) may or may not be suitable to compensate it. For example, chromatic dispersion lends itself well to DSP compensation [1], whereas polarization-dependent gain of Raman amplifiers does not [2], [3]. In the case of laser PN, older analog amplitude shift keying (ASK) systems compensate this by adjusting receiver bandwidth [4], whereas modern coherent systems use DSP.…”

mentioning

confidence: 99%

Dimensioning BCH Codes for Coherent DQPSK Systems With Laser Phase Noise and Cycle Slips

Leong

Larsen

et al. 2014

J. Lightwave Technol.

Self Cite

Abstract-Forward error correction (FEC) plays a vital role in coherent optical systems employing multi-level modulation. However, much of coding theory assumes that additive white Gaussian noise (AWGN) is dominant, whereas coherent optical systems have significant phase noise (PN) in addition to AWGN. This changes the error statistics and impacts FEC performance. In this paper, we propose a novel semi-analytical method for dimensioning binary Bose-Chaudhuri-Hocquenghem (BCH) codes for systems with PN. Our method involves extracting statistics from pre-FEC bit error rate (BER) simulations. We use these statistics to parameterize a bivariate binomial model that describes the distribution of bit errors. In this way, we relate pre-FEC statistics to post-FEC BER and BCH codes. Our method is applicable to pre-FEC BER around 10 −3 and any post-FEC BER. Using numerical simulations, we evaluate the accuracy of our approach for a target post-FEC BER of 10 −5 . Codes dimensioned with our bivariate binomial model meet the target within 0.2 dB signal-to-noise ratio (SNR).

“…Fiber attenuation, polarization mode dispersion and nonlinear effects are neglected. The CD compensation is implemented by using a frequency domain equalizer (FDE) with appropriate parameters [4,5], and the signal equalization is carried out based on the constant modulus algorithm (CMA) [2]. The BER is estimated from a data sequence of 2 17 bits.…”

Section: Numerical Simulations and Analysismentioning

confidence: 99%

“…Coherent optical detection allows the significant equalization of transmission system impairments such as chromatic dispersion (CD), polarization mode dispersion (PMD), phase noise (PN), and fiber nonlinearities (FNLs) in the electrical domain by using the powerful digital signal processing (DSP) [1][2][3][4][5][6][7]. The carrier phase estimation (CPE) can be effectively implemented by employing the feedforward and the feedback algorithms [7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Analytical BER performance in differential n-PSK coherent transmission system influenced by equalization enhanced phase noise

Popov

et al. 2015

Optics Communications

Self Cite

Long-haul high speed optical transmission systems are significantly distorted by the interplay between the electronic chromatic dispersion (CD) equalization and the local oscillator (LO) laser phase noise, which leads to an effect of equalization enhanced phase noise (EEPN). The EEPN degrades the performance of optical communication systems severely with the increment of fiber dispersion, LO laser linewidth, symbol rate, and modulation format. In this paper, we present an analytical model for evaluating the performance of bit-error-rate (BER) versus signal-to-noise ratio (SNR) in the n-level