| 摘要 |
PURPOSE:To make it possible to separate and measure only the effect of material dispersion with high precision by halving light amplitude-modulated with a single sine wave, by causing them to strike optical fibers differing in length and by measuring a phase difference between detection signals by varying the wavelength of light. CONSTITUTION:Light from variable wavelength light source 1, when passing through external modulator 2, is amplitude-modulated with a high-frequency signal from electric signal generator 3. This modulated light is branched into two by branching filter 4; one is incident to optical fiber 5, and the other to optical fiber 6 differing in length from optical fiber 5. Lights having propagated in optical fibers 5 and 6 are converted into electric signals by detectors 8 and 9 and phase difference measuring instrument 9 measures the phase difference. Next, the wavelength of light source 1 is slightly varied to measure the phase difference again and the wavelength is sequentially varied to measure a phase shift to the wavelength, so that the effect of material dispersion will be obtained. |
