CONTINUOUS-WAVE MEASUREMENT OF THE FIBER NONLINEAR REFRACTIVE-INDEX

We propose a technique for measuring the nonlinear refractive index of fiber based on transmission-coefficient measurements in a fiber Sagna c interferometer. In contrast with traditional methods, the proposed m ethod uses a single optical source operating in cw mode and direct int ensity measurement, enabling one to avoid the errors caused by fiber d ispersion and uncertainty of spectral peak difference measurements tha t occur with pulse-based methods. The nonlinear refractive index in 20 -mol. % GeO2 fiber Tvas measured to he (3.1 +/- 0.2) x 10(-16) cm(2) W -1 at 1064 nm. (C) 1998 Optical Society of America.