The measurement of chromatic dispersion in single-mode fibers by interferometric loop

A method for chromatic dispersion measurement in long-length fibers (1-10 km) based on the application of an interferometric loop (IL) with phase modulation and lamp/monochromator light source is described. The wavelength region of the measurement is 1.1-1.6 mu m and the dynamic range is >15 dB. The reproducibility error of the measured group delay and chromatic dispersion is 40 ps/km and 0.1 ps/km-nm respectively. The results obtained by the IL method and Nd-YAG/Raman laser technique are compared. The measured dispersion agrees with the theoretical results calculated from the refractive index profile of the preform. The influence of the type of phase modulation and the length source spectral width on the accuracy of chromatic dispersion measurements by IL technique is analyzed theoretically.<
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