Energy-Efficient Digital Signal Processing for Fiber-Optic Communication Systems
Doctoral thesis, 2019

Modern fiber-optic communication systems rely on complex digital signal processing (DSP) and forward error correction (FEC), which contribute to a significant amount of the over-all link power dissipation. Bandwidth demands are evergrowing and circuit technology scaling will due to fundamental reasons come to an end; energy-efficient design of DSP is thus necessary both from a sustainability perspective and a technical perspective. This thesis explores energy-efficient design of the sub-systems that are estimated to contribute to the majority of the receiver application-specific integrated-circuit power dissipation: chromatic-dispersion compensation, dynamic equalization, nonlinearity mitigation, and forward error correction. With a focus on real-time-processing circuit implementation of the considered algorithms, aspects such as finite-precision effects, pipelining, and parallel processing are explored, the impact on compensation and correction performance is investigated, and energy-efficient circuit implementations are developed. The sub-systems are investigated both individually, and in a system context. DSP designs showing significant energy-efficiency improvements are presented, as well as very high-throughput, energy-efficient, FEC designs. The subsystems are also considered in the context of datacenter interconnect links, and it is shown that DSP-based coherent systems are feasible even in power constrained settings.

Digital Signal Processing

Forward Error Correction

Fiber Optic Communication

Application Specific Integrated Circuits

Communication Systems

Non-linear Impairment Mitigation

EB, EDIT-building, Rännvägen 6
Opponent: Dr. David Hillerkuss, Senior Scientist, Optical and Quantum Laboratory, Huawei, Munich, Germany.


Christoffer Fougstedt

Chalmers, Computer Science and Engineering (Chalmers), Computer Engineering (Chalmers), Electronics Systems

Filter Implementation for Power-Efficient Chromatic Dispersion Compensation

IEEE Photonics Journal,; Vol. 10(2018)

Journal article

Dynamic Equalizer Power Dissipation Optimization

2016 Optical Fiber Communications Conference and Exhibition,; (2016)

Paper in proceedings

Time-Domain Digital Back Propagation: Algorithm and Finite-Precision Implementation Aspects

Optical Fiber Communications Conference and Exhibition,; (2017)p. Article no 7937325-

Paper in proceedings

Finite-Precision Optimization of Time-Domain Digital Back Propagation by Inter-Symbol Interference Minimization

Proceedings of 43rd European Conference and Exhibition on Optical Communications (ECOC),; Vol. 2017-September(2017)p. 1-3

Paper in proceedings

ASIC Implementation of Time-Domain Digital Back Propagation for Coherent Receivers

IEEE Photonics Technology Letters,; Vol. 30(2018)p. 1179-1182

Journal article

ASIC Implementation of Time-Domain Digital Backpropagation with Deep-Learned Chromatic Dispersion Filters

2018 European Conference on Optical Communication (ECOC),; Vol. 2018-September(2018)

Paper in proceedings

Low-Power Low-Latency BCH Decoders for Energy-Efficient Optical Interconnects

Journal of Lightwave Technology,; Vol. 35(2017)p. 5201-5207

Journal article

Energy-Efficient High-Throughput VLSI Architectures for Product-Like Codes

Journal of Lightwave Technology,; Vol. 37(2019)p. 477-485

Journal article

Energy-Efficient Soft-Assisted Product Decoders

2019 Optical Fiber Communications Conference and Exhibition (OFC),; (2019)

Paper in proceedings

Christoffer Fougstedt, Oscar Gustafsson, Cheolyong Bae, Erik Börjeson, Per Larsson-Edefors. DSP and FEC Power Dissipation in 400G Coherent Data Center Interconnects

Fiber-optic communication is a keystone of our global communication networks, and is vital to support the modern digital society. In these systems, we use lasers to transmit our data, and we detect the changes in the light at the opposite end of the fiber. This allows us to transmit and receive data very fast and efficiently. However, as the data travels through the transmitter, the fiber, and the receiver, it gets smeared out and misshaped, and noise is added. Due to this, it is hard to figure out what was originally transmitted, and we need to use electronic circuits that attempt to fix the signal.

Since we want to send our information very fast, we also need to be able to correct these issues in the received signal incredibly fast. The electronic circuits apply math to try to twist the data back into its original shape, as well as try to use some added data to figure out where noise may have caused mistakes. However, the math is difficult to process and the circuit can require quite a bit of electrical power. This is an issue, as there are many of these links and the systems are rather densely packed. Power and energy efficiency is thus a very important concern in order to allow for transmission of more data in a sustainable manner.

In this thesis, we investigate ways to design fast and efficient electronic circuits that are good at correcting the errors and distortion of the signal that is transmitted, while still using a low amount of energy in the processing.

Energy-efficient optical fibre communication

Knut and Alice Wallenberg Foundation, 2014-07-01 -- 2019-06-30.

Subject Categories

Computer Engineering

Communication Systems

Other Electrical Engineering, Electronic Engineering, Information Engineering

Areas of Advance

Information and Communication Technology



Technical report D - School of Computer Science and Engineering, Chalmers University of Technology: 175D

Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 4632


Chalmers University of Technology

EB, EDIT-building, Rännvägen 6

Opponent: Dr. David Hillerkuss, Senior Scientist, Optical and Quantum Laboratory, Huawei, Munich, Germany.

More information

Latest update

9/2/2019 8