Optimization of Transmitter-Side Signal Rotations in the Presence of Laser Phase Noise
Journal article, 2020

The effects of transmitter-side multidimensional signal rotations on the performance of multichannel optical transmission are studied in the presence of laser phase noise. In particular, the laser phase noise is assumed to be uncorrelated between channels. To carry out this study, a simple multichannel laser-phase-noise model that has been experimentally validated for weakly-coupled multicore-fiber transmission is considered. As the considered rotation scheme is intended to work in conjunction with receiver-side carrier phase estimation (CPE), the model is modified to further assume that imperfect CPE has taken place, leaving residual phase noise in the processed signal. Based on this model, two receiver structures are derived and used to numerically optimize transmitter-side signal rotations through Monte Carlo simulations. For reasonable amounts of residual phase noise, rotations based on Hadamard matrices are found to be near-optimal for transmission of four-dimensional signals. Furthermore, Hadamard rotations can be performed for any dimension that is a power of two. By exploiting this property, an increase of up to 0.25 bit per complex symbol in an achievable information rate is observed for transmission of higher-order constellations.

phase noise

Multichannel

optical communications

signal processing

rotation

Author

Arni Alfredsson

Chalmers, Electrical Engineering, Communication and Antenna Systems, Communication Systems

Erik Agrell

Chalmers, Electrical Engineering, Communication and Antenna Systems, Communication Systems

Magnus Karlsson

Chalmers, Microtechnology and Nanoscience (MC2), Photonics

Henk Wymeersch

Chalmers, Electrical Engineering, Communication and Antenna Systems, Communication Systems

Journal of Lightwave Technology

0733-8724 (ISSN)

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Swedish Research Council (VR), 2018-12-01 -- 2021-12-31.

Subject Categories

Telecommunications

DOI

10.1109/JLT.2020.2981883

More information

Latest update

3/21/2020