4 Splicing of optical fibres and installation of fibre optic links
4.2 Procedure

- Two lengths of around 100 mm should be roughly cut from a spool of fibre to be joined again.
- Firstly, using the strippers, the primary and secondary coating layers of the fibre were removed up to approximately 50mm from each end, leaving only the cladding and the core intact.
  - Isopropyl alcohol on a tissue should be used to clean any remaining coating from the exposed cladding.
- The exposed fibre core and cladding should be cut cleanly using the cleaver, to ensure a flat and non-angled surface.
- The fibre should be placed in the v-groove of the cleaver such that the end of the fibre should be extended sufficiently to reach the opposite side of the cutter so that the fibre would be cut rather than bent.
- The fibre is then clamped in position using a spring-loaded clip (silver, left of frame).
  - The mechanism at the bottom of the cleaver should be depressed and the upper part lowered to cleave the fibre. It is essential not to use excessive force for this, as the cut quality may be compromised.

Cleaver with fibre clamped and ready to be cut.

- After both have been successfully cut, we can move onto the actual splicing of the fibres.
- The two fibre ends are placed in the v-grooves of the splicer.
  - It is important that no coating remains on the fibre at the parts where the height is levelled – if it is, the angle of the end of the fibre may be increased and the splice quality decreased. The fibre ends should be as close as possible to the electrodes, but should not overlap the central line between them. When the fibres are correctly positioned, they should be clamped in place and the cover of the splicer can be closed.
- The splicer should then be switched on if it isn’t already, and the ‘Set’ button pressed – the splicer will then fine-tune the positioning of the fibres to try to align their axes and bring them as close as possible together.

Splicer with fibres positioned close to the electrodes in the centre, held in place by spring-loaded clamps.
Automatic gap setting by the splicer and the spliced fibres.

If the positioning and / or the cut quality is particularly bad, the splicer will display a warning on-screen and the fibres can be removed and repositioned or recut. If the conditions are satisfactory, however, the ‘Set’ button can be pressed again and the splicing process will be initiated. A voltage is applied across the electrodes and the ends of the fibres are spliced.

Final appearance of a splice with protection coating.