A technique for measuring optical fiber transmission using the time dispersion of Cerenkov radiation

A technique based on measurement of time dispersion in a δ‐function Cerenkov pulse has been developed for determining the attenuation coefficient α (λ) of low‐loss optical fibers. The time domain amplitude distribution of the transmitted polychromatic pulse is transformed to the wavelength domain by accurate measurement of the differences in arrival times of spectral bands isolated by interference filters. Since the Cerenkov pulses are generated in the fiber by a short burst of relativistic electrons, α (λ) can be measured over a wide and continuous range of path lengths without breaking the fiber. The technique has been demonstrated over the 500–800‐nm spectral region for fiber lengths up to 800 m.