There is provided an exit pupil expander (EPE) for use in a diffractive display, the EPE comprising a plurality of diffractive zones on a waveguide and a plurality of non-diffractive zones between at least some of the diffractive zones.

Systems, devices, and methods of manufacturing optical engines and laser projectors that are well-suited for use in wearable heads-up displays (WHUDs) are described. Generally, the optical engines of the present disclosure integrate a plurality of laser diodes (e.g., 3 laser diodes, 4 laser diodes) within a single, hermetically or partially hermetically sealed, encapsulated package. Photonic integrated circuits having grating couplers thereon may be used to wavelength multiplex beams of light emitted by the plurality of laser diodes into a coaxially superimposed aggregate beam. Such optical engines may have various advantages over existing designs including, for example, smaller volumes, better manufacturability, faster modulation speed, etc. WHUDs that employ such optical engines and laser projectors are also described.

Systems, devices, and methods of manufacturing optical engines and laser projectors that are well-suited for use in wearable heads-up displays (WHUDs) are described. Generally, the optical engines of the present disclosure integrate a plurality of laser diodes (e.g., 3 laser diodes, 4 laser diodes) within a single, hermetically or partially hermetically sealed, encapsulated package. Photonic integrated circuits having grating couplers thereon may be used to wavelength multiplex beams of light emitted by the plurality of laser diodes into a coaxially superimposed aggregate beam. Such optical engines may have various advantages over existing designs including, for example, smaller volumes, better manufacturability, faster modulation speed, etc. WHUDs that employ such optical engines and laser projectors are also described.

Aspects of the disclosure relate to apparatus for the fabrication of waveguides. In one example, an angled ion source is utilized to project ions toward a substrate to form a waveguide which includes angled gratings. In another example, an angled electron beam source is utilized to project electrons toward a substrate to form a waveguide which includes angled gratings. Further aspects of the disclosure provide for methods of forming angled gratings on waveguides utilizing an angled ion beam source and an angled electron beam source.

A surface grating coupler for polarization splitting or diverse includes a planar layer and an array of scattering elements arranged in the planar layer at intersections of a first set of concentric elliptical curves crossing with a second set of concentric elliptical curves rotated proximately 90 or 180 degrees to form a two-dimensional (2D) grating. Additionally, the grating coupler includes a first waveguide in double-taper shape and a second waveguide in double-taper shape respectively for split or diverse an incident light into the 2D grating into two output light to two output ports with a same (either TE or TM) polarization mode or one output port with TE polarization mode and another output port with TM polarization mode. The polarization diverse grating coupler is required to test multiple polarization sensitive photonics components and can be used with other single polarization grating coupler via a fiber array to perform wafer-level testing.

A surface grating coupler for polarization splitting or diverse includes a planar layer and an array of scattering elements arranged in the planar layer at intersections of a first set of concentric elliptical curves crossing with a second set of concentric elliptical curves rotated proximately 90 or 180 degrees to form a two-dimensional (2D) grating. Additionally, the grating coupler includes a first waveguide in double-taper shape and a second waveguide in double-taper shape respectively for split or diverse an incident light into the 2D grating into two output light to two output ports with a same (either TE or TM) polarization mode or one output port with TE polarization mode and another output port with TM polarization mode. The polarization diverse grating coupler is required to test multiple polarization sensitive photonics components and can be used with other single polarization grating coupler via a fiber array to perform wafer-level testing.

A grating coupler having first and second ends for coupling a light beam to a waveguide of a chip includes a substrate configured to receive the light beam from the first end and transmit the light beam through the second end, the substrate having a first refractive index n1, a grating structure having curved grating lines arranged on the substrate, the grating structure having a second refractive index n1, wherein the curved grating lines have line width w and height d and are arranged by a pitch , wherein the second refractive index n2 is less than first refractive index n1, and a cladding layer configured to cover the grating structure, wherein the cladding layer has a third refractive index n3.

A grating coupler having first and second ends for coupling a light beam to a waveguide of a chip includes a substrate configured to receive the light beam from the first end and transmit the light beam through the second end, the substrate having a first refractive index n1, a grating structure having curved grating lines arranged on the substrate, the grating structure having a second refractive index n1, wherein the curved grating lines have line width w and height d and are arranged by a pitch , wherein the second refractive index n2 is less than first refractive index n1, and a cladding layer configured to cover the grating structure, wherein the cladding layer has a third refractive index n3.

A bichromatic grating coupler comprises a two-dimensional diffraction grating structure, including a first sub-grating having a first periodic structure and a second sub-grating having a second periodic structure. The first and second sub-gratings are superimposed with respect to each other in the diffraction grating structure. A first optical port is coupled to the diffraction grating structure along a first direction, and a second optical port is coupled to the diffraction grating structure along a second direction. The first optical port is configured to direct a first light beam having a first wavelength to the diffraction grating structure, such that the first light beam is diffracted in a first direction by the first sub-grating. The second optical port is configured to direct a second light beam having a second wavelength to the diffraction grating structure, such that the second light beam is diffracted in a second direction by the second sub-grating.

Structures for a grating coupler and methods of fabricating a structure for a grating coupler. A silicide layer is formed on a patterned section of a semiconductor layer. The grating structures of a grating coupler are formed over the silicide layer and the section of the semiconductor layer.