WDM Networks and Transmission

This topic is concentrated on contributions to the ACTS-project METON in co-operation with CBT 3 and MIC. The overall purpose of the METON project is to develop an optical WDM-based transport layer to support an ATM/SDH network in providing, cost-effectively, a significant number of subscribers with a multi-service network as well as demonstrating the results in a WDM network based on the Stockholm Gigabit Network. MIC, CBT 3 and CBT 4 have developed a WDM and an Add/Drop multiplexer based on silica-on-silicon technology. The main contribution from CBT 4 has been to develop a WDM transmission simulation program and necessary models for optical components (e.g. nonlinear fiber, optical filters) in order to evaluate the transmission characteristics. The program is called STONE (Simulation Tool for Optical NEtworks).
Within the area of CW transmitters for WDM networks the stability of fiber DFB lasers has been investigated in co-operation with CBT 3 and MIC (Mikroelektronik Centret).
The influence of Stimulated Raman Scattering (SRS) on WDM transmission has been included in an optical network simulator at British Telecom Laboratories as a part of an industrial Ph.D. program.
With increases in transmission speed as well as in network complexity, the optical phase characteristics of components used in optical communication systems might turn out to be a critical parameter. In order to evaluate the importance of the phase it is essential to be able to measure its wavelength dependence accurately.
A phase-shift set-up has been built and the dispersion properties of components such as filters, add-drop multiplexers, arrayed waveguide grating multiplexers, etc., have been characterised successfully.
The measured phase characteristics will be related to observed systems impairments through numerical simulation as well as transmission experiments.
Publications: P1449, P1451, P1456 and P1459.
The project has been moved to COM by Dec. 31, 1998.