As bit rates of optical fibre communication are increased, chromatic dispersion increasingly becomes a problem. Optical means of compensation have been traditionally used. However, the rapid increase in available electronic processing power has made electronic chromatic dispersion compensation a viable option leading to an adaptive, low cost integrated solution which avoids additional optical losses. The aim of this thesis is to explore the maximum transmission distance over standard single mode fibre (SSMF) which can be achieved using only electronic signal processing while minimising complexity in the optical domain. The use of feed-forward and decision feedback equalisers in the receiver of an existing intensity-modulated direct-detection (IM/DD) optical link is explored. An increase in the 10 Gb/s transmission distance from 70 to 112 km of SSMF is demonstrated. However, it is shown that this approach is limited by the loss of the optical field phase information after direct detection. Techniques for overcoming this limit by control or measurement of the optical field are reviewed. The rest of the thesis explores the transmission limits of one such technique: electronic predistortion (EPD). Firstly, limits due to the fundamental transmission properties of EPD signals in non-linear fibre are considered. Secondly, the design of the high speed digital signal processing (DSP) for EPD is described, showing the effect of DSP compensator structure, DAC resolution and sample rate on transmission performance. EPD is shown to be capable of ultra-long haul DWDM operation over SSMF. The design of an experimental 10.7 Gb/s transmitter with real time digital signal processing implemented on FPGAs is described. Transmission over 1200 km of SSMF is demonstrated and the performance is assessed in comparison with simulation results. Finally, conclusions concerning the benefits of EPD transmission in comparison with competing technologies are provided. Areas for further research are identified.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:505252 |
| Date | January 2008 |
| Creators | Watts, Philip Michael |
| Publisher | University College London (University of London) |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://discovery.ucl.ac.uk/16748/ |
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