Another point of damage consisting of a trench (damage point 2) was located 15 cm from damage point 1. The form of the damage (damage point 1) consisted of a severe bend in the cable and a split and detached cable jacket. External view of damaged optical drop cable. The damaged optical drop cable that was removed from the conduit line is shown in Fig. An investigation revealed damage to the optical drop cable in the conduit line about 30 cm from the handhole entrance. That cable had four fibers in the same conduit line.

Just after the installation, we received a report about an interruption in the optical communication service provided by the previously installed optical drop cable. Configuration of underground facilities where optical drop cable was damaged. Finally, the polypropylene string is removed.įig. The rod is then removed, and the polypropylene string is used to install a metallic cable. The installation involves first laying a rod for cables and using the rod to lay a polypropylene string. We investigated the cause of the damage to the optical drop cable.Ī new metallic cable was installed in the conduit line connecting a handhole to a multi-dwelling unit ( Fig. One case involved an optical drop cable that was damaged during the installation of a new metallic cable along a conduit line. Fault case of damage to an optical drop cable Failures of access network facilities the Access Network Engineering Group investigated in 2012. Therefore, we report here the fault cases of optical fiber cables investigated in 2012.įig. We reported fault cases of field assembly connectors in optical access facilities in a previous issue (July 2011). The figure indicates that optical fiber cable and optical connection devices account for nearly half of the total failures. We investigated a range of failure items in 2012, as shown in Fig. The Access Network Engineering Group has been investigating failures that occur in access network facilities including optical fiber cables and metallic cables. In contrast, the number of subscribers using PSTN (Public Switched Telephone Network) consisting of metallic cables was recorded at 27 million as of the end of the same period. The number of FLET’S HIKARI optical fiber broadband service subscribers reached over 17.8 million as of the end of March 2014.

Optical fiber network