Abstract: An optical waveguide comprises two out-diffused optical waveguide sections an in-diffused optical waveguide section, and two narrow transition region intimately connecting the out-diffused waveguide sections and the in-diffused waveguide section. This waveguide structure can decrease the level of in-plane scattering caused by surface irregularities and reduce the difficulty of coupling light into and out of the waveguide. The structure can be made to perform as a transverse magnetic mode filter and increase the intensity of light focussed into the guide beyond the limits imposed by the optical damage resistance of a strictly in-diffused waveguide.

Abstract: An optical waveguide comprises two out-diffused optical waveguide sections, an in-diffused optical waveguide section, and two narrow transition regions intimately connecting the out-diffused waveguide sections and the in-diffused waveguide section. This waveguide structure can decrease the level of in-plane scattering caused by surface irregularities and reduce the difficulty of coupling light into and out or the waveguide. The structure can be made to perform as a transverse magnetic mode filter and increase the intensity of light focussed into the guide beyond the limits imposed by the optical damage resistance of a strictly in-diffused waveguide.