Deutsch

Modern Methods for Optical Communication Networks

Staff

Prof. Dr.-Ing. Herbert Haunstein    

Dipl.-Ing. Markus Mayrock   

Dipl.-Ing. Martin Belzner      

Introduction in optical communication networks

Optical Transport Networks

For the development of future communication networks the increasing convergence of data, video and audio transmission networks is expected. Especially for the improvement of existing access and metro networks it is expected that Layer-2-VPNs (Virtual Private Networks) based on MPLS (Multi-Protocol Label Switching) technology, so called "Pseudowires" and VPLS (Virtual Private LAN Services), will play an important role In parallel the dynamic of the transport network will increase. Bandwidth management will no longer be controlled via a centralized management system but decentralized in and by the network itself (Automatic Switched Transport Networks, ASTN). Therefore the existing network layers must cooperate in an appropriate way in order to transport the data efficiently.

Teaching

Elective Lectures

 Lightwave Transmission Systems (OptÜ)

The increasing information exchange drives the need for high-performance transmission capacity at low prices. The global fiber network provides closer and closer interconnection between economic centers worldwide. During the last years an extremely fast development of dense wavelength division multiplex (WDM) techniques has been established. This development has allowed an enormous increase in transmission capacity over optical fiber. Today's commercially available systems achieve capacities of 2.56Tbps (e.g. 64 wavelengths carrying 40Gbps) on a single fiber over a distance of 1000km. At 10Gbps 128 wavelengths over 4000km are state of the art in terrestrial core networks. For shorter distances (Metropolitan area) higher data rates are requested as well. The increasing internet applications drives the information exchange between high-speed computer connections (e.g. router farms). Hence a rapid increase of Gigabit Ethernet (GigE) and 10G Ethernet Connections is expected. The lectures are concentrating on the description of optical transmission systems for high bit rates over single-mode fibers, based on models used in communications engineering. The transmission channel can be thought ideal at low bit rates, e.g. 155Mbps or 622Mbps. At larger bit rates linear and nonlinear distortions of the optical signal have to be taken into account. The lectures will focus on finding appropriate models for the physical effects utilized in the components and implementation of suitable algorithms for simulation, in order to provide a fundamental understanding of modern optical fiber transmission systems. (more...)

Optical Communications Networks (OptK)

While data transport over the last mile is dominated by analogue modems, ISDN and X-DSL over copper cable or wireless transmission standards like DECT, GSM, CDMA and in the future also UMTS, long-haul transmission systems utilize optical transport standards like SDH /SONET and in future OTN. These standards define the protocols at the network interfaces for combining the different data streams as well as the interfaces for the physical optical transport. Due to the rapid growth of data traffic in local area networks (LANs) a strong increase of Gigabit Ethernet (GigE) and 10G Ethernet connections is expected. As a result the Internet Protocol (IP) is becoming a serious competitor for the SDH/SONET standard. Therefore both transport mechanisms have to be combined into an efficient transport network. The lectures are considered to provide a fundamental understanding of modern fiber optic networks.  (more…)

Seminars

Selected Chapters of Information Transmission

Topics for optical transmission are also within the scope of the seminar "Selected Chapters of Information Transmission". In the past optical topics were, among other things: e.g. physical limits in optical transmission, modulation formats, synchronisation, transmission, optical/electrical regeneration, optical monitoring and optical MIMO systems. Further information about current seminars can be found here.

Research Fields

Simulation of Optical Transmission Systems in Optical Networks

• Improvement of simulation models for application in optical networks. Expansion to dynamic procedures (activation and deactivation of channels)

Optimal Modulation Formats for Optical Transmission Systems

• Research of modern information transmission concepts (transmitter and receivers) in high bit rate transmission and their cost efficient implementation

Design of Adaptive Optical Receivers with Optical/ Electrical Equalization

• Apply equalization techniques  on the special characteristics of the optical channels

• Investigation of control techniques based on signal processors and FPGAs for optical data transmission

• Synchronization in optical information transmission

Utilization of Modern Concepts for Dimensioning Flexible Optical Networks

• Monitoring of optical transparent networks, fault detection and fault localization

• Information exchange for network management (path setup, protection switching)

Dimensioning and Control of Optical Access, Metro and Core Networks 

• Interworking of different layers in the optical network in access, metro and core networks for an efficient data transport

• Control mechanisms for flexible optical networks (ASON/GMPLS)

Current Projects