Topic
Polarization mode dispersion
About: Polarization mode dispersion is a research topic. Over the lifetime, 5147 publications have been published within this topic receiving 80055 citations. The topic is also known as: PMD.
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TL;DR: The probability that a channel of a wavelength-division multiplexed system never incurs an outage, and the range of frequency over which the parameters that characterize the temporal statistics of the differential group delay are correlated are correlated.
Abstract: We elaborate on a recently proposed model of the temporal dependence of polarization mode dispersion in long fiber links. We evaluate the probability that a channel of a wavelength-division multiplexed system never incurs an outage, and the range of frequency over which the parameters that characterize the temporal statistics of the differential group delay are correlated.
23 citations
TL;DR: In this article, the channel equalizer (CE) based on independent component analysis (ICA) for optical OFDM systems without using training symbols (TSs) is studied. And the authors propose a channel matrix initialization method to solve the permutation indeterminacy and complex uncertain scaling problems in ICA.
Abstract: We study the channel equalizer (CE) based on independent component analysis (ICA) for optical orthogonal-frequency-division-multiplexing (OFDM) systems without using training symbols (TSs). We begin by studying mathematical ICA models of optical OFDM systems and considering both the direct-detection optical OFDM (DDO-OFDM) and polarization division multiplexing coherent-detection optical OFDM (PDM-CO-OFDM) systems. One purpose of this paper is to provide a comprehensive study of ICA-based CE in both DDO-OFDM and CO-OFDM systems. Next, we propose a channel matrix initialization method to solve the permutation indeterminacy and complex uncertain scaling problems in ICA for both DDO-OFDM and PDM-CO-OFDM systems. Several algorithms are then investigated for ICA-based CEs including maximization of negentropy (MN), maximum likelihood (ML), minimization of mutual information (MMI), and fast ICA. It is found that the ICA-based CEs using MN, ML, and MMI can successfully recover the OFDM signal. Through both simulation and experiment, we show that in comparison to conventional TSs-based CEs with and without inter-symbol frequency-domain averaging (ISFA) and adaptive decision-directed CE, ICA-based CEs can provide slightly better or similar performances for both SP and DP optical OFDM systems with QPSK and 16-QAM modulations. Specifically, apart from higher spectral efficiency, the ICA-based CEs show significant better chromatic dispersion and polarization mode dispersion (PMD) tolerances than TSs-based CEs with ISFA in PDM-CO-OFDM systems over long-haul transmission.
23 citations
TL;DR: In this article, an endless optical polarisation tracking speed of 100 krad/s was demonstrated for a 64-hour measurement with mean and maximum polarisation errors of 0.096 and 0.220 rad, respectively.
Abstract: For the first time, an endless optical polarisation tracking speed of 100 krad/s is demonstrated. During a 64-hour measurement, a polarisation trajectory of 18 gigaradian length was tracked with mean and maximum polarisation errors of 0.096 and 0.220 rad, respectively.
23 citations
TL;DR: In this paper, a block-wise version of blind time equalizer (CMA) is proposed to counter the inter-symbol interference generated by the chromatic dispersion and the polarization mode dispersion.
Abstract: In polarization multiplexing based coherent optical transmission, two main kinds of impairements have to be counter-acted: 1) the inter-symbol interference generated by the chromatic dispersion and the polarization mode dispersion and 2) the frequency offset. Usually adaptive approaches are carried out to mitigate them. Since the channel is very slowly time-varying, we propose to combat these impairements by using block-wise methods. Therefore, we introduce two new algorithms: the first one is a block-wise version of blind time equalizer (such as CMA), and the second one estimates the frequency offset in block-wise way. These algorithms are suitable for PSK and QAM constellations. By simulation investigations, we show that they outperform the standard approach in terms of convergence speed only at a moderate expense of computational load. We also experimentally evaluate their performance using 8-PSK real data traces and off-line processing which takes into account other physical impairments such as phase noise and non-linear effects.
23 citations
Patent•
19 May 2000
TL;DR: In this article, a dispersion compensator was proposed to compensate for the unwanted chromatic dispersion, dispersion slope, and polarization mode dispersion in a VIPA-based system.
Abstract: The present invention provides a dispersion compensator which utilizes a Virtually Imaged Phased Array (VIPA), gratings, and birefringent wedges to moderate chromatic dispersion, dispersion slope and polarization mode dispersion. The dispersion compensator in accordance with the present invention propagates the composite optical signal in a forward direction; separates the wavelengths in the band of wavelengths in each of the plurality of channels, where each of the wavelengths in the band is spatially distinguishable from the other wavelengths in the band; spatially separates each band of wavelengths in the plurality of channels; spatially separates each wavelength of each separated band of wavelengths into a plurality of polarized rays; and reflects the plurality of polarized rays toward a return direction, where dispersion is added to the reflected plurality of polarized rays such that the unwanted chromatic dispersion, dispersion slope, and PMD are compensated. The dispersion compensator provides simultaneous tunable compensation of these various dispersions utilizing a single apparatus. A system which utilizes the compensator is thus cost effective to manufacture.
22 citations