Field Measurement of PON Branches With End-Reflection-Assisted Brillouin Analysis

Loss distributions of branched fibers in field-installed and in-service passive optical networks are measured from a central office for the first time by using end-reflection-assisted Brillouin analysis. The statistical properties of branch lengths, their differences below outside optical splitters, and the Brillouin frequency shift (BFS) of installed fibers, which are key parameters in the design of the proposed technique, are also investigated. A complete loss distribution measurement for individual branched fibers was successfully achieved by compensating for BFS variation in the field with a frequency-shift averaging technique.