Embodiments include a fiber to photonic chip coupling system including a collimating lens which collimate a light transmitted from a light source and an optical grating including a plurality of grating sections. The system also includes an optical dispersion element which separates the collimated light from the collimating lens into a plurality of light beams and direct each of the plurality of light beams to a respective section of the plurality of grating sections. Each light beam in the plurality of light beams is diffracted from the optical dispersion element at a different wavelength a light beam of the plurality of light beams is directed to a respective section of the plurality of grating sections at a respective incidence angle based on the wavelength of the light beam of the plurality of light beams to provide optimum grating coupling.

A waveguide illuminator includes adjacent linear and slab waveguide areas. An input light beam is guided in a linear waveguide, is split into a plurality of sub-beams to propagate in individual linear waveguides to a slab waveguide area and form an output light beam in the slab waveguide area. An array of out-couplers is disposed in the slab waveguide area. The array of out-couplers out-couples portions of the output light beam forms an array of out-coupled beam portions for illuminating a display panel. Locations of the array of out-couplers are coordinated with locations of individual pixels of the display panel, thereby improving efficiency of light utilization by the display panel.

A waveguide illuminator includes adjacent linear and slab waveguide areas. An input light beam is guided in a linear waveguide, is split into a plurality of sub-beams to propagate in individual linear waveguides to a slab waveguide area and form an output light beam in the slab waveguide area. An array of out-couplers is disposed in the slab waveguide area. The array of out-couplers out-couples portions of the output light beam forms an array of out-coupled beam portions for illuminating a display panel. Locations of the array of out-couplers are coordinated with locations of individual pixels of the display panel, thereby improving efficiency of light utilization by the display panel.

A biochip device includes a stratified structure, a light coupler, and an optofluidic portion. The stratified structure includes a top layer having a refractive index n.sub.1, a bottom layer having a refractive index n.sub.3, and an intermediate layer between the top and bottom layers having a refractive index n.sub.2. The light coupler optically couples a light source and the top layer to generate waves that are guided in a plurality of directions inside the top layer. The optofluidic portion is supported on a surface of the top layer and includes a hybridizing chamber containing a hybridizing solution and pads supported on the surface of the top layer and situated within the hybridizing chamber. Probe molecules are deposited on the pads. The refractive index n.sub.2 of the intermediate layer is greater than or equal to a highest index of refraction of the hybridizing chamber and the hybridizing solution.

A surface-relief grating comprises a plurality of grating ridges including a first material, and a layer of a second material conformally deposited on surfaces of the plurality of grating ridges. A first region of the surface-relief grating is characterized by a first grating depth and a first duty cycle greater than a first threshold value. A second region of the surface-relief grating is characterized by a second grating depth and a second duty cycle lower than a second threshold value that is lower than the first threshold value. A difference between the first grating depth and the second grating depth is less than 20% of the second grating depth.

Structures including an edge coupler and methods of fabricating a structure including an edge coupler. The structure includes a dielectric layer including an edge, a waveguide core region on the dielectric layer, and multiple segments on the dielectric layer. The waveguide core region has an end surface, and the waveguide core region is lengthwise tapered toward the end surface. The segments are positioned between the waveguide core region and the edge of the dielectric layer. A waveguide core has a section positioned over the waveguide core region in an overlapping arrangement. The waveguide core has an end surface, and the section of the waveguide core is lengthwise tapered toward the end surface.

Structures including an edge coupler and methods of fabricating a structure including an edge coupler. The structure includes a dielectric layer including an edge, a waveguide core region on the dielectric layer, and multiple segments on the dielectric layer. The waveguide core region has an end surface, and the waveguide core region is lengthwise tapered toward the end surface. The segments are positioned between the waveguide core region and the edge of the dielectric layer. A waveguide core has a section positioned over the waveguide core region in an overlapping arrangement. The waveguide core has an end surface, and the section of the waveguide core is lengthwise tapered toward the end surface.

Disclosed are apparatus and methods for optical coupling in optical communications. In one embodiment, an apparatus for optical coupling is disclosed. The apparatus includes: a planar layer; an array of scattering elements arranged in the planar layer at a plurality of intersections of a first set of concentric elliptical curves crossing with a second set of concentric elliptical curves rotated proximately 90 degrees to form a two-dimensional (2D) grating; a first taper structure formed in the planar layer connecting a first convex side of the 2D grating to a first waveguide; and a second taper structure formed in the planar layer connecting a second convex side of the 2D grating to a second waveguide. Each scattering element is a pillar into the planar layer. The pillar has a top surface whose shape is a concave polygon having at least 6 corners.

A device includes a light source, a waveguide layer, and a light director layer. The light source emits illumination light. The waveguide layer includes a cladding layer and an optical waveguide. The cladding layer provides a top planar surface of the waveguide layer and the optical waveguide is immersed in the cladding layer and includes a light input coupler. The light director layer includes a bottom planar surface that is disposed on the top planar surface of the waveguide layer. The light director layer also includes a light director that receives and directs the illumination light to the light input coupler as shaped light. The light director is configured to tilt the illumination light to give the shaped light a tilt angle with respect to the light input coupler.

A waveguide illuminator includes an input waveguide, a waveguide splitter coupled to the input waveguide, and a waveguide array coupled to the waveguide splitter. The waveguide array includes an array of out-coupling gratings that out-couple portions of the split light beam to form an array of out-coupled beam portions for illuminating a display panel. The out-coupling gratings may be apodized to reduce light scattering by the gratings. Additionally, gaps between the out-coupling gratings along the waveguides may be filled by gap gratings and/or etched grooves running parallel to the waveguides.