Interlaboratory comparisonof mode transition matrices

An interlaboratory measurement round-robin was conducted by the University of Colorado and three industrial members of the Electronic Industries Association. A computational definition of mode transition matrices (MTM's) is presented, and its relationship to the basic theory of power propagation in multimode fibers is detailed. Measured data from the round-robin were used to calculate MTM's for the test components, which included four connectors, two sections of fiber cable, two power splitters, and two short fiber segments. The diagonal elements of the (2 × 2) MTM's determined from the near-field data were found to have a laboratory-to-laboratory standard deviation of approximately 10% of the average value. The off-diagonal elements were found to have a standard deviation approaching their mean value. The inherent launch dependence of MTM's is investigated as a source of the observed variation. Other sources of uncertainty such as errors in determining the core radius are alsoconsidered. Finally the implications of these results for the problem of characterizing components' intensive multimode fiber systems are discussed.