Print Email Facebook Twitter Blind Polarization Demultiplexing of Shaped QAM Signals Assisted by Temporal Correlations Title Blind Polarization Demultiplexing of Shaped QAM Signals Assisted by Temporal Correlations Author Bajaj, V. (TU Delft Team Sander Wahls) Van de Plas, Raf (TU Delft Team Raf Van de Plas; VanderBilt University) Wahls, S. (Karlsruhe Institut für Technologie) Date 2024 Abstract While probabilistic constellation shaping (PCS) enables rate and reach adaption with finer granularity [1] (Cho and Winzer, 2009), it imposes signal processing challenges at the receiver. Since the distribution of PCS-quadrature amplitude modulation (QAM) signals tends to be Gaussian, conventional blind polarization demultiplexing algorithms are not suitable for them [2] (Johnson et al., 1998). It is known that independently and identically distributed (iid) Gaussian signals, when mixed, cannot be recovered/separated from their mixture. For PCS-QAM signals, there are algorithms such as [3] and [4] Dris et al. (2019) and Athuraliya et al. (2004) which are designed by extending conventional blind algorithms used for uniform QAM signals. In these algorithms, an initialization point is obtained by processing only a part of the mixed signal, which have non-Gaussian statistics. In this article, we propose an alternative method wherein we add temporal correlations at the transmitter, which are subsequently exploited at the receiver in order to separate the polarizations. We will refer to the proposed method as frequency domain (FD) joint diagonalization (JD) probability aware-multi modulus algorithm (pr-MMA), and it is suited to channels with moderate polarization mode dispersion (PMD) effects. Furthermore, we extend our previously proposed JD-MMA [5] (Bajaj et al., 2022) by replacing the standard MMA with a pr-MMA, improving its performance. Both FDJD-pr-MMA and JD-pr-MMA are evaluated for a diverse range of PCS (entropy $\mathcal {H}$) of 64-QAM over a first-order PMD channel that is simulated in a proof-of-concept setup. A MMA initialized with a memoryless constant modulus algorithm (CMA) is used as a benchmark. We show that at a differential group delay (DGD) of 10% of symbol period T$_{\text{symb}}$ and 18 dB SNR/pol., JD-pr-MMA successfully demultiplexes the PCS signals, while CMA-MMA fails drastically. Furthermore, we demonstrate that the newly proposed FDJD-pr-MMA is robust against moderate PMD effects by evaluating it over a DGD of up to 40% of T$_{\text{symb}}$. Our results show that the proposed FDJD-pr-MMA successfully equalizes PMD channels with a DGD up to 20% of T$_{\text{symb}}$. Subject and optical fiber communicationCorrelationDemultiplexingdigital signal processingOptical fiber dispersionPolarization demultiplexingprobabilistic constellation shapingProgrammable logic arraysQuadrature amplitude modulationSignal processing algorithmsSymbols To reference this document use: http://resolver.tudelft.nl/uuid:bfd0d299-b573-4a1d-aab8-a085d9284d87 DOI https://doi.org/10.1109/JLT.2023.3315370 Embargo date 2024-03-14 ISSN 0733-8724 Source Journal of Lightwave Technology, 42 (2), 560-571 Part of collection Institutional Repository Document type journal article Rights © 2024 V. Bajaj, Raf Van de Plas, S. Wahls Files PDF Blind_Polarization_Demult ... ations.pdf 1.56 MB Close viewer /islandora/object/uuid:bfd0d299-b573-4a1d-aab8-a085d9284d87/datastream/OBJ/view