About the research area Optical communications
Fiber-optic communication systems carry most of today’s global internet traffic and other data communication services. This is essential for video conferencing, telemedicine, video-on-demand, data processing and storage in the cloud, “Internet of Things”, and 4G and 5G mobile services. As the potential improvements by legacy wavelength-division multiplexing hardware becomes costlier or even infeasible, optical communications is paving the way to meet the challenges of increasing bandwidth demanded by society.
Our group focuses on new methods to increase the capacity of existing optical links through software optimizations. Our goal is to extend transmission distances, increase bandwidth, and reduce energy consumption, and through this, we strive to achieve long term social and environmental impact.
Our four main focus areas are:
- Modulation techniques
- Understanding and mitigating nonlinear distortion for high power transmissions
- Power efficiency for data centers
- Adaptive optical networks
Publications in optical communications, Chalmers Publication Library
See also the publication lists of the participating researchers, via the links below at the bottom of the webpage.
Our group has a number of ongoing projects, and a good
track record of attracting research funding from Swedish Foundation for
Strategic Research, the Swedish Research Council, EU Horizon 2020,
See a list of our projects below.
The received signals in an optical transmission experiment are analyzed in real time (instruments on the left).
Our group works with Chalmers Innovation Office on identifying intellectual assets and developing utilisation strategies. We are active in publication and conferences to spread our research knowledge. Through media exposure, we also communicate to educate the public on optical communications.
We also believe that collaboration is essential in order to transform our innovations into practical added-value applications for society. We have a long history of cooperating with industry, universities, research institutes and government.
Cristian Czegledi and Erik Agrell discuss how to represent polarized light geometrically.
Within the FORCE center, we collaborate closely with the Photonics Laboratory at the Department of Microtechnology and Nanoscience, which provides the photonics expertise, including knowledge of lasers, fibers, detectors, and amplifiers.
We also collaborate with the VLSI Design Group at the Department of Computer Science and Engineering, which provides expertise in the design and implementation of electronic signal processing.
Together, the three groups comprise a truly interdisciplinary research environment in order to address system-wide research challenges and attain innovative solutions. We have together received international attention at the leading international conferences and journals.
Our collaboration partners outside Chalmers include for example University College London, UK, Royal Institute of Technology in Stockholm, University of Virginia, USA, and University of Toronto in Canada.
The collaborations have resulted in numerous research visits, joint projects, and co-authored scientific articles.
At the Communication Systems Group at Chalmers, we apply our expertise in digital communication theory (coding, modulation, detection, and estimation), to increase the efficiency of optical communication systems at both the physical layer (signal processing, modulation and coding, and parallelization) as well as the network layer (switching, routing, multiplexing, and spectrum assignment). Because communication systems are complex, close collaboration is needed between industry, society and research in order to make tangible and sustainable impact.
Industrial collaboration projects are designed based on mutual benefit for all parties involved. It is common that projects are based on the general practice of open innovation within Chalmers, but with special agreements when appropriate to account for, e.g., industrial competitiveness and IP-related issues.
If you are interested to get in touch, please contact Professor Erik Agrell.
Research projects in optical communications
fiber networks are indispensable for our society’s information
infrastructure. The demands for high-capacity, reliable communications
will continue to increase for many years, due to new emerging services
such as cloud processing and telepresence. This project addresses one of
the fundamental bottlenecks in the development of next-generation
optical networks, namely interference...
> Technologies for spatial-division multiplexing: The next frontier in optical communications
Optical fiber communication systems constitute the backbone of Internet. In this project, we propose to analyze and demonstrate concepts to reach substantially higher transmission throughput than in todays optical communication systems. This is essential, as the currently used technology approach, using single-mode optical fibers...
> Towards flexible and energy-efficient datacentre networks
The growing popularity of cloud and multimedia services is increasing the traffic volume that datacentres need to handle, leading to serious bottlenecks in datacentre networks in terms of both capacity and energy consumption. Reducing the power required by the inter- and intra-rack communication inside the datacentre...
> Energy-efficient optical fibre communication
Optical communication links and networks are essential for the Internet backbone as well as for interconnects used in data centres and high-performance computing systems. Therefore, the energy consumption in optical transmission systems is an increasingly important problem within our information society...
> Coding for optical communications in the nonlinear regime (COIN)
The rapid increase in data traffic in the past years and traffic forecasts will lead to capacity exhaust in the optical fibre communications infrastructure which carries over 95% of all data services. The optical fibre channel is nonlinear, that is, its properties, namely its refractive index, is dependent on optical intensity, and at high power densities, ...
> Polarization-aware fiber optic transmisson
Fiber-optic communications forms the basis of the Internet and is such of utmost importance in our society. This project aims at demonstrating novel groundbreaking signaling schemes for such links, that have the potential to dramatically simplify coherent receivers...
> Signal shaping in optical communications
Higher and higher demands are placed on the digital backbone infrastructure, which is based almost entirely on fiber-optic communication links. This project aims to boost the performance of such links using signal shaping to adapt the transmitted signal alphabet to the capacity-achieving distribution for the underlying channel.
> Energy-efficient and high-speed transmission in optical fiber communication (from January 2018)
> Coherent receiver syncronization
Synchronization refers to processing at the receiver-side of a digital communication link, in order to recover optimal sampling times and compensate for frequency and phase offsets induced by physical components. In optical communication systems, the design of synchronization algorithms is especially challenging due to extremely high baud rates, minimal dedicated processing capabilities, stringent latency constraints, and hardware deficiencies...
> Advanced modulation and coding
In this project, we analyze multilevel
modulation formats suitable for coherent, optical transmission.
Modulation formats are optimized under ideal conditions as well as
considering realistic optical impairments, such as self-phase modulation
and transmitter/receiver saturation...
> Coded modulation
Coded modulation (CM) refers to a system
where an encoder is combined with a higher order modulator with more
than one bit per symbol to increase the spectral efficiency. Examples of
encoders can be simple block codes or convolutional codes, to more
advanced encoders like turbo codes...
> Theory for intensity-modulated links
With the rapidly increasing demand for large-scale fiber-to-the-home, the cost of transmission equipment is crucial. In this project, we develop communication theory for links consisting of a low-cost laser diode (e.g., a vertical-cavity surface-emitting laser, VCSEL) in the transmitter, whose intensity but not phase can be modulated. Similarly, the receiver is a photo diode that detects the intensity of the received lightwave...
> Power-efficient terabit/s transmission
Fiber optic communications has, and will play, a pivotal role in our future, being a major enabling technology in our increasingly Internet-centric society. The aggregated data rates in e.g. Internet cross-connects are now so high that terabit/s transmission systems and line cards are being required, and solutions for e.g. terabit Ethernet are being discussed.
> Adaptive optical networks
internet traffic is expected to increase fourfold in the next five
years. This traffic will be highly time-varying and has led to the
introduction of flexible, so-called "elastic," optical networks. In such
networks, light-paths are set up and optically routed from sources to
destinations with no intermediate electro-optic conversions...
> MIMOptics: Multi-mode coherent fiber-optical communications
society’s demand for increasing data rates is continuing unabated,
today mainly to support streaming video and cloud computing. According
to a conservative estimate from Cisco, the global Internet traffic
increases 29% per year, leading to a ten-fold increase by 2022...