Abstract: Optical circuits, in optical waveguide structures, are provided by making grating elements in patterns defined by perturbations of the refractive index of the waveguide material. An optical waveguide including ultraviolet (UV) photosensitive material is carried by a substrate to provide a waveguide assembly. The assembly is overlaid with a first mask being nontransparent to ultraviolet light and having a transparent aperture which defines an area of the optical waveguide for formation of an optical circuit. The first mask also includes registration targets. A grating mask with ports for passing ultraviolet light is removably clamped in a space registered relationship over the first mask, to provide a process assembly which is vibration tolerant. Exposing the grating mask to an ultraviolet radiation source, such as a UV lamp, forms the desired perturbations to affect the grating elements. The grating mask is removed and is reusable.