Field Experience with Fiber-Optic Cable Installation, Splicing, Reliability, and Maintenance
The experience obtained during the installation of more than 700 sheath km of fiber-optic cable is summarized. These include in-building, underground (duct), aerial, buried, and underwater installations. In general, no special precautions are required except to maintain the specified pull tension and cable bend radius. Field splicing is discussed and results are given on splice losses with and without splice loss monitoring with the optical time domain reflectometer. A 28 percent learning curve for fusion splicing is derived. Reliability data on 312 sheath km of installed cable and field splices are presented. Most of the cable failures were in the "uncontrollable extrinsic category," and most of these were due to complete cable cuts. Finally, restoration is reviewed with emphasis on troubleshooting, repair, emergency restoration, and offset breaks.
Fusion splicing machine for optical fibres
A fusion splicing machine has been developed with an integrated fibre cutter and support for the splice case inset with splice magazine. The optical fibres and the electrodes can be manipulated, with the result that the splice losses are minimal and optical fibres with different melting points can be fused. Since the splices are not mechanically strong, tension relief facilities for the splice play an important part.
Prediction of net pressure on pressure equalized cavities
Abstract A numerical model has been developed for prediction of net pressure on pressure equalized cavities. The results based on this model show good agreement with those obtained from mock-up tests. Parametric studies verify that reductions in cladding load are possible, with proper design of curtain walls.