Modeling and Compensation of Polarization Effects in Fiber-Optic Communication Systems
Doctoral thesis, 2018

Optical communication systems that exploit the orthogonality between two polarizations of light convey information over optical fibers by modulating data over the two polarizations. In an idealized scenario, the two polarizations propagate through the fiber without interfering. However, this is not the case for practical fibers, which suffer from various imperfections that lead to polarization-related interference between the two polarizations. This thesis is concerned with polarization effects that arise in communication systems over optical fibers. In particular, we consider modeling and compensation of such effects, and their impact on and improvement of nonlinearity mitigation algorithms.

The impact of an impairment on the performance of a transmission system can be understood via a channel model, which should describe the behavior of the channel as accurately as possible. A theoretical framework is introduced to model the stochastic nature of the state of polarization during transmission. The model generalizes the one-dimensional carrier phase noise random walk to higher dimensions, modeling the phase noise and state of polarization drift jointly as rotations of the electric field and it has been successfully verified using experimental data. Thereafter, the model is extended to account for polarization-mode dispersion and its temporal random fluctuations. Such models will be increasingly important in simulating and optimizing future systems, where sophisticated digital signal processing will be natural parts.

The typical digital signal processing solution to mitigate phase noise and drift of the state of polarization consists of two separate blocks that track each phenomenon independently and have been developed without taking into account mathematical models describing the impairments. Based on the proposed model for the state of polarization, we study a blind tracking algorithm to compensate for these impairments. The algorithm dynamically recovers the carrier phase and state of polarization jointly for an arbitrary modulation format. Simulation results show the effectiveness of the proposed algorithm, having a fast convergence rate and an excellent tolerance to phase and polarization noise.

The optical fiber is a nonlinear medium with respect to the intensity of the incident light. This effect leads to nonlinear interference as the intensity of light increases, which made nonlinear interference mitigation techniques to be an intensively studied topic. Typically, these techniques do not take into account polarization-mode dispersion, which becomes detrimental as the nonlinear effects interact with polarization-mode dispersion. We study digital-domain nonlinear interference mitigation algorithms that take into account polarization-mode dispersion by i) reversing the polarization effects concurrently with reversing the nonlinear effects and by ii) mitigating only the polarization-insensitive nonlinear contributions. These algorithms will be increasingly important in future optical systems capable of performing large bandwidth nonlinear interference mitigation, where even small amounts of polarization-mode dispersion become a limiting factor.

nonlinear compensation

Channel model

model-based

polarization demultiplexing

polarization-mode dispersion

polarization drift

backpropagation

PMD

DBP

HC2
Opponent: Professor Mark Shtaif, Tel Aviv University, Israel

Author

Cristian Bogdan Czegledi

Chalmers, Electrical Engineering, Communication, Antennas and Optical Networks

Polarization Drift Channel Model for Coherent Fibre-Optic Systems

Scientific Reports,; Vol. 6(2016)p. 21217-

Journal article

Temporal Stochastic Channel Model for Absolute Polarization State and Polarization-Mode Dispersion

2017 Optical Fiber Communications Conference and Exhibition (OFC),; (2017)p. Th3F.2 -

Paper in proceeding

Modulation Format Independent Joint Polarization and Phase Tracking for Coherent Receivers

Journal of Lightwave Technology,; Vol. 13(2016)p. 3354-3364

Journal article

Polarization-Mode Dispersion Aware Digital Backpropagation

42nd European Conference on Optical Communication, ECOC 2016; Dusseldorf; Germany; 18 September 2016 through 22 September 2016,; (2016)p. 1091-1093

Paper in proceeding

A PMD-adaptive DBP receiver based on SNR optimization

2018 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXPOSITION (OFC),; (2018)

Paper in proceeding

Digital backpropagation accounting for polarization-mode dispersion

Optics Express,; Vol. 25(2017)p. 1903-1915

Journal article

Volterra Series Digital Backpropagation Accounting for PMD

European Conference on Optical Communication,; (2017)p. 1-3

Paper in proceeding

Subject Categories

Telecommunications

Communication Systems

Signal Processing

Infrastructure

C3SE (Chalmers Centre for Computational Science and Engineering)

ISBN

978-91-7597-702-7

Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 4383

Publisher

Chalmers

HC2

Opponent: Professor Mark Shtaif, Tel Aviv University, Israel

More information

Latest update

2/27/2018