Dry Central Tube Ribbon Cables for the Outside Plant Environment

摘要

Historically, optical fiber cables for the Outside Plant (OSP) environment have employed filling compounds to immediately surround the fibers within the core tube or buffer tubes. The primary function of filling compound is to impede the migration of water within the interior of the cable. Additional benefits provided by filling compounds include increasing hydrostatic resistance to compressive forces and vibrational damping. The performance and reliability of filled cables has been demonstrated over the past 15 years. However, during cable installation, filling compound is generally a nuisance. The most significant difficulty is removal of the filling compound and cleaning of the fiber units before splicing. This is a time-consuming process that increases expense and reduces productivity during installation operations. Filling compound can also contribute significantly to the total weight of cables, increasing the equipment and personnel required for long-haul installations. Filling compounds tend to be sticky or greasy, and therefore are a housekeeping annoyance to installers. In recent years, to overcome these drawbacks, many cable manufacturers have offered new designs that minimize the amount of filling compound, as reviewed briefly here. The focus of this paper is the development of a family of new central tube ribbon cables that completely eliminate all filling compounds and/or oils within the central core tube. This new design family has been applied to fiber counts ranging from 12 to 21 6, in both metallic and dielectric sheaths. All of the cables in this family are fully compliant with the Telcordia GR-20 standard requirements for Outside Plant cables. Compared to conventional filled OSP cables, the new family of cables has equivalent or better optical, mechanical and environmental performance. We also summarize the results of a rigorous battery of installation simulation tests that show the performance of this family of cables is generally better than that of standard filled cables. Finally, we present time-study results that demonstrate that these new cables offer installers substantial time and cost savings during splicing operations.