s plastic cladding but the core is silica. The all plastic fibre value of 0.18dB/km. is of even lower cost but its performance is also lower. The extrinsic fibre losses owe their presence to the practical difficulties in making and using fibres. Extrinsic losses include 53.1.2 Optical fibre characteristics scattering due to the departure from perfect core-cladding interface, bending losses, losses due to the permanent joining of fibre (splic- In order to use the fibre in communication systems the potential user ing), loss of connectors and coupling losses at the input and output. needs to know their optical, electrical and mechanical charac- The scattering at the core-cladding interface results in both mode 53/6 Fibre optic communications The physical mechanism is similar and the loss is known as wave- guide loss. Fibre can be pulled in lengths between a few metres to a few Attenuation kilometres and since system length range from a few kilometres to [8Bkm] tens of kilometres, permanent joint techniques are required. The Measured total loss permanent jointing fibre is known as splicing. Two broad categories of splicing techniques have emerged: fusion splicing (welding) and mechanised splicing. Fusion splicing is accomplished by the fusion of two pre-aligned fibres by the application of heat. The heat can be generated by an Lstimated electric arc or flame, and the technique is easy to apply and yields loss neglecting impurity absorption remarkable low losses in the field. For example fusion splicing hand edge yields routinely 0.2dB loss per splice. One drawback of fusion splicing is the reduction of the tensile strength of the fibre in the vicinity of the fused splice because of the heating of the fibre. For Rayleigh this reason fusion splices are packaged with the aim of reducing the scuttering tensile load in the vicinity of the splice. Mechanical splicing, before the introduction of fusion splicing, was the only way of permanently joining two fibres. The basic idea behind this mechanical splicing is the alignme