Overcoming the Optical Networks Capacity Crunch
Peter J. Winzer
Head of the Optical Transmission Systems and Networks Research Department at Bell Labs, Holmdel, NJ, United States
With network traffic growing exponentially between about 30% and 60% per year, depending on application segment and geography, fiber-optic transport networks are rapidly approaching their fundamental Shannon capacity limits. In fact, today’s Wavelength-Division Multiplexing (WDM) products are already within a factor of 3 to 6 from their fundamental limits, with little room for economically attractive growth. By 2020, leading-edge network operators will require capacities that are physically impossible to implement using conventional optical transmission technologies. Of all five physical dimensions that can be used for information transmission by electromagnetic waves, “space” is the one not yet exploited. Introducing parallelism in the spatial domain (i.e., Space-Division Multiplexing, SDM) is thus the only long-term viable solution on the horizon to overcome the optical networks capacity crunch. After reviewing the state-of-the-art and the challenges in optical transport networks research and development, we will examine long-term capacity scaling through SDM. We will explore the implications of ultimately unavoidable spatial crosstalk on optical networking hardware and architectures, and point to spatial superchannels and multiple-input-multiple-output (MIMO) digital signal processing as a solution.
Peter J. Winzer received his Ph.D. in electrical engineering from the Vienna University of Technology, Austria, in 1998. Supported by the European Space Agency (ESA), he investigated photon-starved space-borne Doppler lidar and laser communications using high-sensitivity digital modulation and detection. At Bell Labs since 2000, he has focused on various aspects of high-bandwidth fiber-optic communication systems, including Raman amplification, advanced optical modulation formats, multiplexing schemes, and receiver concepts, digital signal processing and coding, as well as on robust network architectures for dynamic data services. He contributed to several high-speed and high-capacity optical transmission records with interface rates from 10 Gb/s to 1 Tb/s, including the first 100G and the first 400G electronically multiplexed optical transmission systems and the first field trial of live 100G video traffic over an existing carrier network. Since 2008 he has been investigating and globally promoting spatial multiplexing as a promising option to scale optical transport systems beyond the capacity limits of single-mode fiber. He currently heads the Optical Transmission Systems and Networks Research Department at Bell Labs in Holmdel, NJ. He has widely published and patented and is actively involved in technical and organizational tasks with the IEEE Photonics Society and the Optical Society of America (OSA), currently serving as Editor-in-Chief of the IEEE/OSA Journal of Lightwave Technology and as Program Chair of the 2015 Optical Fiber Communication Conference (OFC). Dr. Winzer is a Bell Labs Fellow and a Fellow of the IEEE and the OSA.