Loss Cause Identification by Evaluating Backscattered Modal Loss Ratio Obtained With 1 mm Band Mode Detection OTDR
We propose a novel diagnostic technique that uses 1 mm band mode detection optical time domain reflectometry (1 mm OTDR) to identify the loss causes such as macrobends and fusion splices, of single mode fibers. 1 mm OTDR, which employs 1 mm band probe pulses and a mode selective coupler operating in the same band, enables us to individually observe the fundamental (LP01) and the second order (LP11) modes of the backscattered light generated in the two mode region of single mode fibers. Evaluating the ratio of losses occurring in the LP01 to LP11 modes of the backscattered light allows us to determine whether the cause of loss is a macrobend or a fusion splice. A proof of concept demonstration is performed for two kinds of widely used single mode fibers, and the results show that macrobending and fusion splice losses can be clearly identified.
Journal of Lightwave Technology