MEASUREMENT OF THE NONLINEAR REFRACTIVE-INDEX IN OPTICAL-FIBER BY THE CROSS-PHASE-MODULATION METHOD WITH DEPOLARIZED PUMP LIGHT

Depolarized pump light is used in measurements of the nonlinear refractive index, nz, in optical fiber by the cross-phase-modulation method. High measurement repeatability within +/-1% is obtained by this method. The nonlinear refractive index is determined for dispersion-shifted fiber, standard single-mode fiber, pure silica-core single-mode fiber, and dispersion-compensating fiber as 3.35 x 10(-20), 2.96 x 10(-20), 2.79 x 10(-20), and 4.44 x 10(-20) m(2)/W, respectively, at 1.55 mu m. This shows that the nonlinear refractive indices of the optical fibers differ greatly according to glass composition.