Abstract: A method for producing a Bragg grating in an optical waveguide device such as an optical fiber. The optical fiber is exposed to a UV source through a phase mask and this produces a Bragg grating on the fiber. The grating on the fiber is overexposed such that the gratings are stronger than desired. The fiber is then annealed to stabilize the gratings left behind. The gratings left behind are still stronger than desired. The fiber is then exposed to a point source laser that reduces the index change for selected portions. This trims the existing grating to result in the desired grating strength.

Abstract: The present invention seeks to provide a GFF with a technique amenable to manufacturing in large volume and having a filter with a more precise control of the spectral response.

Abstract: A method of fabricating a strongly photosensitive optical waveguide is comprised of locally heating at least a portion of a weakly photosensitive optical waveguide for a period of time sufficient to increase the density of defects associated with photosensitivity in the heated portion of the waveguide core.

Abstract: An index grating is imprinted in the core of an optical fiber using a specially designed silica glass phase grating mask. The phase mask is held in close proximity to the optical fiber. Laser irradiation of the phase mask with ultraviolet light at normal incidence imprints (photoinduces) into the optical fiber core the interference pattern created by the phase mask.

Abstract: Efficient, narrow-band rocking filters have been made in polarization-maintaining monomode optical fiber by photoinducing periodic birefringent gratings along the length of the fiber. These gratings, fabricated with a period chosen to provide synchronous coupling between the two principal states of polarization of the LP.sub.01 mode at a preselected wavelength, gently rock to and fro the principal polarization axes of the fiber. To photoinduce the grating, the fiber is exposed periodically along its length to a U.V. light beam which is incident at right angles to the geometrical axis of the fiber and is directed .pi./4 radians with respect to the principal axes. Efficient polarization mode conversion at 1.3 .mu.m with the fiber gratings are obtained.

Abstract: An index grating is imprinted in the core of an optical fiber using a specially designed silica glass phase grating mask. The phase mask is held in close proximity to the optical fiber. Laser irradiation of the phase mask with ultraviolet light at normal incidence imprints (photoinduces) into the optical fiber core the interference pattern created by the phase mask.