The Effects of Environmental Exposure on Fiber Optic Connectors in Outside Plant Closures

摘要

The growing use of fiber optic facilities in the access infrastructure has resulted in the need for increased physical flexibility to support rapid service deployment, dual homing, network re-configuration and faster service restoration. In order to address this need for physical flexibility, some network providers have deployed cross-connect closures in outside plant environments. However, there have been continuing concerns regarding the long-term reliability and integrity of the connections within these outside plant cross-connect closures. In 1999, Telcordia Technologies in cooperation with Ameritech, Bell Atlantic, Bell South, Southwestern Bell and US WEST conducted a reliability assessment of some of these closures. Above grade, below grade and pole mounted closures were reviewed in four areas of the country. The locations were chosen as being representative of the environments and installations within the continental United States. Temperature and humidity sensors were placed in some of the installations. The data from the sensors combined with that from field visits was used to characterize the environments and conditions of exposure. Samples of SC, ST, and D4 jumpers and cable ends were collected for laboratory examination and testing. Most of the closures included in the study were deployed in the early 1990s so that samples and experience data from four to seven years are included. This paper discusses the metrics of the study, the significant findings and the resulting Telcordia recommendations. Among the findings reported, were that service related problems were rate. Although, above grade closures are vulnerable to outside plant hazards such as motor vehicle impacts. In fact, one closure included in this study was struck by a motor vehicle. The environments were characterized by instances of extreme temperature variations, extended and repeated periods of condensation, and evidence of a wide variety of contaminants.