Digital filters for coherent optical receivers.

By Seb J. Savory. Optics Express, 2008

1,147 citations recorded by the source corpus.

Digital filters underpin the performance of coherent optical receivers which exploit digital signal processing (DSP) to mitigate transmission impairments. We outline the principles of such receivers and review our experimental investigations into compensation of polarization mode dispersion. We then consider the details of the digital filtering employed and present an analytical solution to the design of a chromatic dispersion compensating filter. Using the analytical solution an upper bound on the number of taps required to compensate chromatic dispersion is obtained, with simulation revealing an improved bound of 2.2 taps per 1000ps/nm for 10.7GBaud data. Finally the principles of digital polarization tracking are outlined and through simulation, it is demonstrated that 100krad/s polarization rotations could be tracked using DSP with a clock frequency of less than 500MHz.

Subfields: Electrical and Electronic Engineering, Signal Processing

View Paper: https://www.semanticscholar.org/paper/484b12fcee2be07160dc3850306ed0b345515870

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Citations in the corpus

Fiber Impairment Compensation Using Coherent Detection and Digital Signal Processing (2010, background): “11 to improve the performance of SC systems [27].”
The GN-Model of Fiber Non-Linear Propagation and its Applications (2014, background): “In coherent systems, linear transmission impairments can be almost totally compensated for using DSP, with reasonable computational complexity [73].”
Effect of Mode Coupling on Signal Processing Complexity in Mode-Division Multiplexing (2013, background): “each CD equalizer, the number of filter taps (temporal memory measured in sampling intervals) required for compensation with very low power penalty [37], [38] is given by:”
Performance Limits of Nyquist-WDM and CO-OFDM in High-Speed PM-QPSK Systems (2010, background): “The second stage is driven by the constant modulus algorithm (CMA) [7], which is active throughout the simulation.”
Spectrally Efficient Long-Haul Optical Networking Using 112-Gb/s Polarization-Multiplexed 16-QAM (2010, background): “CMA adaptation works particularly well for (single-ring) PSK constellations, where it is often the only adaptation algorithm used [20].”
Fundamentals of Coherent Optical Fiber Communications (2016, background): “Polarization demultiplexing and compensation for PMD have also been demonstrated with the digital coherent receiver [37], where bulky and slow optical-polarization controllers as well as optical-delay lines are eliminated.”
DSP for Coherent Single-Carrier Receivers (2009, methodology): “If no known training symbols are available at the receiver, translating the CMA from a single-input–single-output (SISO) channel to a 2 2 MIMO equalizer [26], as shown in Fig.”
High-Spectral-Efficiency Optical Modulation Formats (2012, methodology): “Chromatic dispersion represents an all-pass filter with quadratic phase [74], which can be compensated using a filter with the inverse phase profile [75].”
Multi-Level, Multi-Dimensional Coding for High-Speed and High-Spectral-Efficiency Optical Transmission (2009, methodology): “The transmission line consisted of 13 spans of 80 km of SSMF (average span loss of 17 dB), 5 spans of 100 km of SSMF (average span loss of 21 dB) and EDFA-only optical amplification.”