Chromatic-dispersion measurement by modulation phase-shift method using a Kerr phase-interrogator

We present a novel approach for the measurement of chromatic-dispersion in long optical fibers using a modulation phase-shift method based on a Kerr phase-interrogator. This approach utilizes a Kerr phase-interrogator to measure the phase variation of a sinusoidal optical signal induced by traveling in a fiber under test as the laser carrier wavelength and the sinusoidal signal frequency are varied. Chromatic-dispersion measurement for several fibers including a standard single-mode silica fiber and a dispersion-shifted fiber is experimentally demonstrated. The ultrafast response of the Kerr phase-interrogator opens the way for real-time monitoring of chromatic-dispersion in kilometers-long optical fibers.