| 摘要 |
PURPOSE:To directly obtain a self-correlation waveform of a distribution against the longitudinal direction of a fluctuation of the inside of a transmission for inducing a mode coupling, and an external factor, by obtaining a self-correlation of a mode coupling distribution by utilizing an optical path length difference between two luminous fluxes allowed to correspond to a difference of mode converting positions. CONSTITUTION:A luminous flux A and a luminous flux B which have been multiplexed by a multiplexer 5 are made incident on a two-mode optical fiber 8 from its one end through a mode selecting element 7. When the light is made incident on the two- mode optical fiber 8 from the multiplexer 5, the mode selecting element 7 selects only one propagation mode of two propagation modes, and only the selected mode is made incident on the two-mode optical fiber 8 and propagated. Subsequently, as for the light emitted from the two-mode optical fiber 8, only a component of the other propagation mode of two propagation modes is extracted by a mode selecting element 9. The light of this mode 2 is brought to a photoelectric conversion by a photodetector 10, supplied to a waveform recorder 11, and the interference intensity is recorded. In such a way, a self-correlation of a mode coupling distribution between two propagation modes can be obtained. |
