ITU-T Recommendations

Recommendation ITU-T L.400/L.12 specifies splices of single-mode and multimode optical fibres. It describes suitable procedures for splicing that should be carefully followed in order to obtain reliable splices between single optical fibres or ribbons. The procedures apply to both single optical fibres and ribbons (mass splicing).
Splices are critical points in the optical fibre network, because they strongly affect the quality and lifetime of links. In fact, the splice should ensure high quality and stability of performance with time. High quality in splicing is usually characterized by low splice loss and tensile strength near that of the fibre proof test level. Splices should be stable over the design life of the optical fibre link under its expected environmental conditions.
At present two technologies, fusion and mechanical, can be used for splicing glass optical fibres and the choice between them depends upon the expected functional performance and considerations of installation and maintenance. These splices are designed to provide permanent connections.
The following elements have been modified in this edition of Recommendation ITU-T L.400/L.12:
– maximum attenuation of fibre splices depending on the alignment method (active core, active cladding and passive V-groove alignment);
– maximum attenuation for mechanical splices;
– validation of splicing procedure is added with average and maximum attenuation (97% of the splices) of fibre splices;
– the appendix with Japanese experience is removed;
– inclusion of Appendix II, which shows the increase in attenuation when splicing different types of optical fibres by taking into account the mode field diameter mismatch, the core-cladding concentricity and the cladding diameter;
– inclusion of Appendix III, which explains the fibre imaging process in fusion splicing machines.