Patent ID: 8260104
Filing Date: 2012-09-04
Classification: G02B

Abstract:
1. An optical apparatus comprising: a substantially planar waveguide substrate; lower cladding formed on the waveguide substrate; a lower waveguide core layer formed on the lower cladding; middle cladding formed on the lower waveguide core layer; an upper waveguide core layer formed on the middle cladding; upper cladding formed on the upper waveguide core layer; and a first waveguide core between the upper and lower waveguide core layers that is separated from the upper and lower waveguide core layers by portions of the middle cladding and that defines an optical waveguide propagation path, wherein a width of the first waveguide core is substantially larger than a thickness of the first waveguide core, and the first waveguide core has a substantially flat upper surface, wherein each one of the lower cladding, the middle cladding, and the upper cladding has a corresponding refractive index that is less than corresponding refractive indices of the lower waveguide core layer, the upper waveguide core layer, and the first waveguide core, and wherein, along a first segment of the propagation path: the width of the first waveguide core is substantially constant; the upper and lower waveguide core layers and the first waveguide core are arranged so as to together form an optical waveguide that guides a first optical mode propagating along the first segment of the propagation path; the upper and lower waveguide core layers extend bilaterally substantially beyond the lateral extent of the first optical mode; and the upper and lower waveguide core layers and the first waveguide core are arranged so that the first optical mode is guided bilaterally by the first waveguide core, from below by the lower waveguide core layer, and from above by the upper waveguide core layer.