The characteristics of optical fiber Bragg reflective filter (FBR) are analyzed on the basis of asymmetric six layer optical waveguide model using an improved perturbation procedure for investigating dielectric gratings. The influences of waveguide structural parameters, mainly the thickness of the high index layer, on the characteristics of FBR are discussed. The experimental method of controlling FBR reflectivity during the fabrication process is given . At 1.55 μm region, FBR devices with reflectivity up to 96% and reflection bandwidth (FWHM) about 1.5 nm are fabricated.