Abstract: A practical realization for achieving and maintaining high-efficiency transfer of light from input and output free-space optics to a high-index waveguide of sub-micron thickness is described. The required optical elements and methods of fabricating, aligning, and assembling these elements are discussed. Maintaining high coupling efficiency reliably over realistic ranges of device operating parameters is discussed in the context of the preferred embodiments.

Abstract: A low loss coupling arrangement between a slab/strip waveguide and a rib waveguide in an optical waveguiding structure formed on a silicon-on-insulator (SOI) platform utilizes tapered sections at the input and/or output of the rib waveguide to reduce loss. Optical reflections are reduced by using silicon tapers (either vertical tapers, horizontal tapers, or two-dimensional tapers) that gradually transition the effective index seen by an optical signal propagating along the slab/strip waveguide and subsequently into and out of the rib waveguide. Loss can be further reduced by using adiabatically contoured silicon regions at the input and output of the rib waveguide to reduce mode mismatch between the slab/strip waveguide and rib waveguide. In a preferred embodiment, concatenated tapered and adiabatic sections can be used to provide for reduced optical reflection loss and reduced optical mode mismatch.

Abstract: A system and method for providing the layout of non-Manhattan shaped integrated circuit elements using a Manhattan layout system utilizes a plurality of minimal sized polygons (e.g., rectangles) to fit within the boundaries of the non-Manhattan element. The rectangles are fit such that at least one vertex of each rectangle coincides with a grid point on the Manhattan layout system. Preferably, the rectangles are defined by using the spacing being adjacent grid points as the height of each rectangle. As the distance between adjacent grid points decreases, the layout better matches the actual shape of the non-Manhattan element. The system and method then allows for electrical and optical circuit elements to be laid out simultaneously, using the same layout software and equipment.

Abstract: A photodetector for use with relatively thin (i.e., sub-micron) silicon optical waveguides formed in a silicon-on-insulator (SOI) structure comprises a layer of poly-germanium disposed to couple at least a portion of the optical signal propagating along the silicon optical waveguide. Tight confinement of the optical signal within the waveguide structure allows for efficient evanescent coupling into the poly-germanium detector. The silicon optical waveguide may comprise any desired geometry, with the poly-germanium detector formed to either cover a portion of the waveguide, or be butt-coupled to an end portion of the waveguide. When covering a portion of the waveguide, poly-germanium detector may comprise a “wrap-around” geometry to cover the side and top surfaces of the optical waveguide, with electrical contacts formed at opposing ends of the detector.

Abstract: A trapezoidal shaped single-crystal silicon prism is formed and permanently attached to an SOI wafer, or any structure including a silicon optical waveguide. In order to provide efficient optical coupling, the dopant species and concentration within the silicon waveguide is chosen such that the refractive index of the silicon waveguide is slightly less than that of the prism coupler (refractive index of silicon≈3.5). An intermediate evanescent coupling layer, disposed between the waveguide and the prism coupler, comprises a refractive index less than both the prism and the waveguide. In one embodiment, the evanescent coupling layer comprises a constant thickness. In an alternative embodiment, the evanescent coupling layer may be tapered to improve coupling efficiency between the prism and the waveguide. Methods of making the coupling arrangement are also disclosed.

Abstract: A multilayer ceramic package for optical devices is disclosed for use in both high and low bit rate applications. A side portion of the multilayer package is formed to provide a multilayer microwave input connection for a high bit rate signal. In an exemplary arrangement, an intermediate ceramic layer of the multilayer structure is defined with an appropriate thickness and metallized on areas of the top and bottom surfaces. This combination thus forms a multilayer microwave connection defined as a microstrip. Other multilayer configurations, for example, a stripline, may also be used. By utilizing a multilayer microwave connection in place of a conventional electrical connection, the impedance of the high frequency input source can be better matched to the optical device.