The optical fibre connecting devices most widely used are splices and connectors. Splices are permanent connections; they may be fusion splices, where the two fibres are fused together or mechanical splices, where the fibres are mechanicall. The optical fibre connecting devices most widely used are splices and connectors. Splices are permanent connections; they may be fusion splices, where the two fibres are fused together or mechanical splices, where the fibres are mechanically posi-tioned in a semi-permanent way. Optical connectors are passive optical components designed to connect t. Thus far, the discussion has been focussed on connectors for standard single-mode fibres, the most widely used fibre for telecom applications. However, there are also connectors for other types of fibres (polarisation maintaining, specialty fibres at shorter wavelengths), for special applications such as very high optical power or particularly hars. Standard single-mode fibres do not maintain a well-defined state of polarisation (SOP) of the light because many effects including reflection from surfaces or stress within the transmitting media (due to moving the fibre or temperature variations) can affect the polarisation of the propagating light. Fig. 10.9 Examples of polarisation-maintaining f. A single particle mated into the core of a fibre can cause significant back reflection, insertion loss, and equipment damage. If high optical power is involved, contamina-tion may even cause a permanent damage. As a consequence, it is of high importance to prevent contamination of connector end faces which may be due to: Mishandling, such as accide. The most common type of fibre coupler is the evanescent field coupler which uses a narrow spacing between two adjacent fibre cores. Because the electromagnetic field extends beyond the cores, coupling between the cores happens. Fibre-based couplers are produced using essentially two different techniques. Most popular is the fused biconical taper te.
