| 摘要 |
PROBLEM TO BE SOLVED: To obtain the transmission delay time and distance of an optical fiber transmission line based on only a reference clock at a reception side. SOLUTION: An optical fiber transmission line 17 with a known refractive index at different wavelengths λ1 and λ2 is used. The same light signals with different wavelengths λ1 and λ2 are simultaneously transmitted from a transmission side λ1 to a reception side. Since the transfer speed of the light signal of each wavelength is determined uniquely by the refractive index and a transmission delay time until the light signal of each wavelength arrives differs according to the distance of a light transmission line, a delay time difference Δt is measured by obtaining the difference of the arrival time of each wavelength based on a reference time 112 at the reception side at the reception side 18. Based on the delay time difference Δt and the refractive index at each wavelength, transmission delay time in the optical fiber and optical fiber transmission distance are calculated only at the reception side. |
