Chromatic dispersion measurements of long optical fibers by means of optical ranging system using a frequency-shifted feedback laser

We describe the experimental results on the chromatic dispersion measurement of long optical fibers by means of optical ranging system using a wavelength-tunable frequency-shifted feedback (FSF) laser. The optical ranging system using an FSF laser has high spatial resolution of several centimeter over 10-km measurement range, and then the dependence of the group delay time of the lightwave in the optical fibers on the wavelength can be directly measured. The chromatic dispersion and the zero-dispersion wavelength of an 80-km-long dispersion shifted fiber was estimated, which is in good agreement with the result obtained by the phase method.