Optical communication over multimode fibres

The research project is concerned with techniques for increasing the transmission rate of a digital data signal over fibre-optic channels, where these use multimode fibres. The properties of fibre-optic channels are first described, together with suitable techniques for generating and detecting light signals. The possible use of fibre bundles in an arrangement of a parallel data-transmission system is then investigated. A detailed experimental investigation has been carried out into the optical cross coupling between individual fibres in a fibre bundle. The results of the experiment support some theoretical predictions by other workers in this field that there is negligible cross coupling between the individual fibres of a fibre bundle. This suggests that it is perfectly feasible to use a fibre bundle in a parallel data-transmission system. However, a consideration of the equipment complexity involved shows that this is unlikely to lead to a cost-effective system. [Continues.]