An optical waveguide comprises one or more upstream diffraction gratings in addition to overlapping first and second downstream diffraction gratings. The one or more upstream diffraction gratings include a first upstream diffraction grating configured to receive display light and to release the display light expanded along a first axis. The first and second downstream diffraction gratings are configured to receive the display light expanded along the first axis and to cooperatively release the display light further expanded along a second axis. The first downstream diffraction grating is arranged on a planar face of the optical waveguide and is further configured to further expand along the first axis the display light expanded along the first axis.

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.

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.

Diffraction grating-based backlighting having controlled diffractive coupling efficiency includes a light guide and a plurality of diffraction gratings at a surface of the light guide. The light guide is to guide light and the diffraction gratings are to couple out a portion of the guided light using diffractive coupling and to direct the coupled-out portion away from the light guide surface as a plurality of light beams at a principal angular direction. Diffraction gratings of the plurality include diffractive features having a diffractive feature modulation configured to selectively control a diffractive coupling efficiency of the diffraction gratings as a function of distance along the light guide surface.

Roughly described, an integrated optical device includes both a PLC chip and an attached SiPh chip. The PLC chip has a PLC waveguide which terminates at an end facet. The SiPh chip has a SiPh waveguide which includes a Bragg grating which diffracts light from the SiPh waveguide toward the PLC chip. The PLC chip also has a turning mirror to reflect light emitted from the Bragg grating onto the end facet of the PLC waveguide. The Bragg grating is designed to direct light emitted from the Bragg grating into the end facet of the PLC waveguide so that after reflecting off the turning mirror the light focuses within one Rayleigh distance of the end facet of the PLC chip.

Roughly described, an integrated optical device includes both a PLC chip and an attached SiPh chip. The PLC chip has a PLC waveguide which terminates at an end facet. The SiPh chip has a SiPh waveguide which includes a Bragg grating which diffracts light from the SiPh waveguide toward the PLC chip. The PLC chip also has a turning mirror to reflect light emitted from the Bragg grating onto the end facet of the PLC waveguide. The Bragg grating is designed to direct light emitted from the Bragg grating into the end facet of the PLC waveguide so that after reflecting off the turning mirror the light focuses within one Rayleigh distance of the end facet of the PLC chip.

Methods and systems for a bi-directional receiver for standard single-mode fiber based on grating couplers may include, in an integrated circuit, a multi-wavelength grating coupler, and first and second optical sources coupled to the integrated circuit: receiving first and second source optical signals at in the integrated circuit using the first and second optical sources, where the second wavelength is different from the first wavelength, receiving a first optical data signal at the first wavelength from an optical fiber coupled to the multi-wavelength grating coupler, and receiving a second optical data signal at the second wavelength from the optical fiber. Third and fourth optical data signals at the first and second wavelengths may be communicated out of the optoelectronic transceiver via the multi-wavelength grating coupler.

Methods and systems for a bi-directional receiver for standard single-mode fiber based on grating couplers may include, in an integrated circuit, a multi-wavelength grating coupler, and first and second optical sources coupled to the integrated circuit: receiving first and second source optical signals at in the integrated circuit using the first and second optical sources, where the second wavelength is different from the first wavelength, receiving a first optical data signal at the first wavelength from an optical fiber coupled to the multi-wavelength grating coupler, and receiving a second optical data signal at the second wavelength from the optical fiber. Third and fourth optical data signals at the first and second wavelengths may be communicated out of the optoelectronic transceiver via the multi-wavelength grating coupler.

An example device includes a nanovoided polymer element, a first electrode, and a second electrode. The nanovoided polymer element may be located at least in part between the first electrode and the second electrode. In some examples, the nanovoided polymer element may include anisotropic voids. In some examples, anisotropic voids may be elongated along one or more directions. In some examples, the anisotropic voids are configured so that a polymer wall thickness between neighboring voids is generally uniform. Example devices may include a spatially addressable electroactive device, such as an actuator or a sensor, and/or may include an optical element. A nanovoided polymer layer may include one or more polymer components, such as an electroactive polymer.

A form birefringent optical element includes a structured layer and a dielectric environment disposed over the structured layer. At least one of the structured layer and the dielectric environment includes a nanovoided polymer, the nanovoided polymer having a first refractive index in an unactuated state and a second refractive index different than the first refractive index in an actuated state. Actuation of the nanovoided polymer can be used to reversibly control the form birefringence of the optical element. Various other apparatuses, systems, materials, and methods are also disclosed.