Minimisation of modal noise in optical-fibre connectors

Modal noise has recently been recognised as a source of interference in multimode optical-fibre systems involving coherent sources and misaligned connectors. This letter describes a technique whereby the effects of fibre misalignment may be minimised by the appropriate design of the connector. The essential principle is that far-field rather than near-field coupling is utilised. A significant reduction in modal noise due to misalignments can be expected using this principle, and the estimated losses are comparable to those in conventional connectors.