To investigate the nonlinear optical properties of metallic nanoparticles in dielectric composite materials, germano-silicate glass optical fibers incorporated with gold nanoparticles were made by using modified chemical vapor deposition technique and solution doping process. The incorporation of the gold nanoparticles was confirmed by the sharp absorption peak appeared near 498.4nm, which was due to the surface plamon resonance absorption of Au nanoparticles. Resonant optical nonlinearities of the fibers were estimated by measuring the peak shift of the fringes obtained from the long-period fiber grating pair upon pumping with Argon laser at 488nm. The resonant nonlinearity was found to be 5.00x10-16m2/W by the incorporation of the gold metal concentration and with the addition of Al3+ ions.© (2007) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.