Measurement of the nonlinear index of silica-core and dispersion-shifted fibers

We have accurately measured the nonlinear refractive index, n(2), of the glass found in silica-core and dispersion-shifted optical fibers. We find that at 1.319 microm the n(2) of silica-core and dispersion-shifted fibers is 2.36 x 10(-16) and 2.52 x 10(-16) cm(2)/W (+/-5%), respectively. We also estimate that the n(2) of germania is three times the n(2) of pure silica. Because the wavelength dependence of n(2) between 1.3 and 1.5 microm is known to be small, our measured values should also be valid at 1.55 microm.