OPTICAL FIBER CHARACTERISTIC MEASURING APPARATUS AND OPTICAL FIBER CHARACTERISTIC MEASURING METHOD

摘要

[PROBLEMS] To completely separate an increased amount of probe light from noise and extend the measuring range while keeping spatial resolution high. [MEANS FOR SOLVING PROBLEMS] Both probe light and pump light are modulated to distinguish the two from each other. Using this modulation, it is possible to separate only the variation of the probe light which is necessary for measuring the characteristics of an optical fiber under test (FUT). This eliminates the necessity of a conventional optical wavelength filter. In addition, since the measuring range is extended while keeping spatial resolution (?z) high, even if the amplitude (?f) of frequency modulation of a light source (1) is widened to some extent, there is no effect from this amplitude (?f) when detecting the variation of the probe light. Accordingly, it is possible to completely separate an increased amount of the probe light from noise and extend the measuring range while keeping the spatial resolution (?z) high.