Application of digital signal processing in coherent optical communication systems

• Main Author: Huang, Dezhao
• Other Authors: Cheng Tee Hiang
• Format: Theses and Dissertations
• Language: English
• Published: 2014
• Subjects: DRNTU::Engineering::Electrical and electronic engineering::Optics, optoelectronics, photonics
• Online Access: http://hdl.handle.net/10356/55449
• Institution: Nanyang Technological University

In this thesis, we study the application of DSP techniques in optical coherent communication systems and propose a few algorithms to improve receiver performance. An accurate two-stage frequency offset estimation (FOE) algorithm is introduced, whose mean square error (MSE) is two orders less than that of the conventional phase difference-based FOE. A low complexity phase interpolation filter is proposed for block-averaging carrier phase estimation (CPE) algorithms. The performance of block estimation with proposed filter is similar to that of the sliding-window estimation. An adaptive joint-polarization carrier phase recovery algorithm is proposed to estimate FO and carrier phase in one block to reduce complexity. Signals from both polarizations are jointly processed for better noise immunity. A decision-aided CPE with selective averaging is introduced. Symbols with significantly large noise are identified and excluded to reduce estimation distortion. Finally, a DSP-based receiver for coherent long-reach optical access network is studied. Issues such as Burst-mode clock data recovery and frequency chirp mitigation are addressed.