| 摘要 |
PROBLEM TO BE SOLVED: To measure a propagation constant at any position in the longitudinal direction of an optical fiber during any propagation mode while keeping the optical fiber non-destructive.SOLUTION: Treatment for obtaining a propagation constant is repeatedly performed while changing a propagation mode of pump pulsed light by a mode conversion/selection switch 15 on the basis of a Brillouin frequency shift (BFS) obtained by requiring the BFS by performing frequency analysis about respective time domains at any different positions of an optical fiber to be measured 16 to a time waveform of Brillouin scattering light A3 propagated behind in the optical fiber to be measured using a Brillouin time domain reflection measuring method (BOTDR). |
