| EPSRC Reference: |
GR/J08126/01 |
| Title: |
SIGNAL PROCESSING TO ACCOMMODATE WAVEFORM DISTORTION IN OPTICAL FIBRE SYSTEMS |
| Principal Investigator: |
Watkins, Dr L |
| Other Investigators: |
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| Researcher Co-Investigators: |
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| Project Partners: |
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| Department: |
Sch of Electronics |
| Organisation: |
Bangor University |
| Scheme: |
Standard Research (Pre-FEC) |
| Starts: |
01 April 1994 |
Ends: |
30 September 1996 |
Value (£): |
93,527
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| EPSRC Research Topic Classifications: |
| Digital Signal Processing |
Optical Communications |
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| EPSRC Industrial Sector Classifications: |
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| Panel History: |
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Summary on Grant Application Form |
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A major aim of this research is to identify and realise novel signal processing functions that are tolerant to optical signal waveform distortion in direct-detection optical fibre communication systems operating at 10 Gbit/s and above. The objectives of the research are to develop suitable models of nonlinear waveform distortion and to extend a theoretical framework for system performance estimation to include these new models. Practical signal processing functions that accommodate waveform distortion may then be identified and realised as distributed structures for a target 10 Gbit/s test bed. The test bed simulates typical repeaterless system in which the benefits of the novel signal designs may be compared with their conventional counterparts. Experimental results will be fed back into the theoretical work.Progress:The design and fabrication of a 3rd order low-pass Butterworth filter for the 10 Gbit/s test bed was undertaken at an early stage in the project. The aim was to establish a suitable fabrication technology for the filters and to provide a standard benchmark for the novel filter designs. A microstrip substrate with a very thin dielectric layer was identified as a suitable material and after some initial fabrication difficulties, the third order Butterworth filter was produced. Full frequency- and time-domain measurements have been made on this filter. The fit to the theoretical target responses is very good and the fabrication process is thus calibrated for future designs. The industrial collaborator, BNR Europe, have given the investigators access to a 10 Gbit/s test bed. The key systems parameters of this test bed have been measured and given to the investigators. Numerical systems simulations undertaken at Bangor with this data have identified a parameter space within which the novel signal processing design may be undertaken. Work now in progress is focused on realising optimised filter designs based on idealised components as distributed structures and to the direct optimisation of these structures. The combination of a tapped delay line filter and low pass filter can provide enhanced benefit in the presence of substantial waveform distortion. Simulation studies have been undertaken that have established the performance improvement of this combination as a function of the number of taps and tap spacing of the tapped delay line filter for a given system. The influence of the choice of low pass filter on the attainable benefit has also been quantified. The theoretical work is well advanced. A rigorous model of waveform distortion has been derived that also encapsulates other major system impairments, such as intersymbol interference. This model has been incorporated into the moment based bound on the system bit error rate which is used to estimate system performance. A new, tighter bound on the error rate has been derived. The modelling work has focused mainly on optically pre-amplified receivers in view of their importance in high speed systems.Publications to date include:Y.R. Zhou and L.R. Watkins, Photonics Tech. Letters, 6 (9), Sep. 1994, p. 1159 - 1161.J.S. Hornsby, L.R. Watkins and Y.R. Zhou, Electronics Letters, 31 (1), 1995, p. 18.Y.R. Zhou and L.R. Watkins, Proc. 11th European Conference on Circuit Theory and Design, Part 1, Davos, Switzerland, Aug. 1993, p. 7 - 11.L.R. Watkins and Y.R. Zhou, IEE Colloquium on High Capacity Optical Communications, London, May, 1994.Y.R. Zhou and L.R. Watkins, CLEO/Europe '94, Amsterdam, Sept. 1994, p. 315 - 316.
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This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk
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Potential use in non-academic contexts |
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This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk
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Impacts |
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| Description |
This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk |
| Summary |
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| Date Materialised |
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Sectors submitted by the Researcher |
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This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk
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| Project URL: |
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| Further Information: |
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| Organisation Website: |
http://www.bangor.ac.uk |