Abstract: The invention provides masks that form fiber Bragg gratings (FBGs) in optical fibers without stitching errors from re-scaling or re-positioning. The invention feathers the pixels of the mask lines by adding, removing, and/or displacing one or more pixels from the edges of the bars and spaces of the mask. The feathering of pixels will affect the FBG being written into the fiber. The feathering operates to shift the effective edge of the bars. This allows the achievement of much finer resolution FBGs than the pixel size of the mask.

Abstract: The present invention is directed to a system and method for designing efficient multi-channel FBG gratings using a pre-compensated phase mask for diffracting light for side-writing the grating on an optical fiber core. A desired phase function of the FBG is generated, specifically tailored to an effective spacing between the phase mask and the optical fiber core. From the phase function a phase mask is pre-compensated to offset diffraction effects associated with each longitudinal position of the FBG receiving light from two corresponding longitudinal positions of the phase mask substantially symmetrically spaced longitudinally relative to each particular longitudinal position of the FBG. The two corresponding longitudinal positions of the phase mask are spaced longitudinally from each other by a spacing determined by the effective spacing between the phase mask and fiber core and by the first order diffraction angle of light through the phase mask.

Abstract: The present invention relates to an athermal tunable filter in which the wavelength and intensity responses of the filter can be independently tuned by moving the location of the filter. The filter is fabricated by recording multiple volume phase holographic gratings in highly stable photosensitive glasses (e.g. Ge-doped fused silica optic fiber preforms). The athermal operation is realized by an innovative design, in which the shift of the effective grating period induced by the thermal-optic effect is automatically compensated by the shift of incident and output beam angles. In addition, by recording the gratings in selected areas, the intensity response of the filter can also be independently tuned.

Abstract: The present invention is directed to a system and method for designing efficient multi-channel FBG gratings using a pre-compensated phase mask for diffracting light for side-writing the grating on an optical fiber core. A desired phase function of the FBG is generated, specifically tailored to an effective spacing between the phase mask and the optical fiber core. From the phase function a phase mask is pre-compensated to offset diffraction effects associated with each longitudinal position of the FBG receiving light from two corresponding longitudinal positions of the phase mask substantially symmetrically spaced longitudinally relative to each particular longitudinal position of the FBG. The two corresponding longitudinal positions of the phase mask are spaced longitudinally from each other by a spacing determined by the effective spacing between the phase mask and fiber core and by the first order diffraction angle of light through the phase mask.

Abstract: The invention provides masks that form fiber Bragg gratings (FBGs) in optical fibers without stitching errors from re-scaling or re-positioning. The invention feathers the pixels of the mask lines by adding, removing, and/or displacing one or more pixels from the edges of the bars and spaces of the mask. The feathering of pixels will affect the FBG being written into the fiber. The feathering operates to shift the effective edge of the bars. This allows the achievement of much finer resolution FBGs than the pixel size of the mask.