PATH TO PROVIDE OTDR MEASUREMENTS OF AN OPTICAL TRANSMISSION SYSTEM THAT INCLUDES OPTICAL ISOLATORS

摘要

A path couples a pair of optical fibers in an optical transmission system. The transmission system includes a plurality of optical amplifiers (17, 18) placed along the transmission line (10, 12). Associated with these optical amplifiers are optical isolators (21) that limit the flow of optical energy to a single direction. The path allows reflected or scattered light from one optical fiber after the optical isolator to be returned via the other optical fiber. This enables an OTDR device to obtain measurement information along the length of the fibers between optical isolators (21).