Measurement of the nonlinear coefficient of optical fibers by femtosecond pulses and spectral interferometry

Accurate measurements of the nonlinear coefficient /spl gamma/ of optical-communication fibers are performed by using 110-fs pulses. The nonlinear phase shift induced by self-phase modulation over a propagation length shorter than 1 m is detected by the spectral-interferometry technique. The value of /spl gamma/ is obtained by comparing the measured frequency-dependent nonlinear phase with the numerical solution of the nonlinear propagation equation.