An example device includes a nanovoided polymer element, which may be located at least in part between the electrodes. In some examples, the nanovoided polymer element may include anisotropic voids, including a gas, and separated from each other by polymer walls. The device may be an electroactive device, such as an actuator having a response time for a transition between actuation states. The gas may have a characteristic diffusion time (e.g., to diffuse half the mean wall thickness through the polymer walls) that is less than the response time. The nanovoids may be sufficiently small (e.g., below 1 micron in diameter or an analogous dimension), and/or the polymer walls may be sufficiently thin, such that the gas interchange between gas in the voids and gas absorbed by the polymer walls may occur faster than the response time, and in some examples, effectively instantaneously.

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.

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.

Integrated-optics systems are presented in which an optically active device is optically coupled with a silicon waveguide via a passive compound-semiconductor waveguide. In a first region, the passive waveguide and the optically active device collectively define a composite waveguide structure, where the optically active device functions as the central ridge portion of a rib-waveguide structure. The optically active device is configured to control the vertical position of an optical mode in the composite waveguide along its length such that the optical mode is optically coupled into the passive waveguide with low loss. The passive waveguide and the silicon waveguide collectively define a vertical coupler in a second region, where the passive and silicon waveguides are configured to control the distribution of the optical mode along the length of the coupler, thereby enabling the entire mode to transition between the passive and silicon waveguides with low loss.

Integrated-optics systems are presented in which an optically active device is optically coupled with a silicon waveguide via a passive compound-semiconductor waveguide. In a first region, the passive waveguide and the optically active device collectively define a composite waveguide structure, where the optically active device functions as the central ridge portion of a rib-waveguide structure. The optically active device is configured to control the vertical position of an optical mode in the composite waveguide along its length such that the optical mode is optically coupled into the passive waveguide with low loss. The passive waveguide and the silicon waveguide collectively define a vertical coupler in a second region, where the passive and silicon waveguides are configured to control the distribution of the optical mode along the length of the coupler, thereby enabling the entire mode to transition between the passive and silicon waveguides with low loss.

A packaged device includes an optical IC having an optical feature therein. An interconnect structure including layers of conductive features embedded within respective layers of dielectric materials overlie the optical feature. The interconnect structure is patterned to remove the interconnect structure from over the optical feature and a dielectric material having optically neutral properties, relative to a desired light wavelength(s) is formed over the optical feature. One or more electronic ICs may be bonded to the optical IC to form an integrated package.

A packaged device includes an optical IC having an optical feature therein. An interconnect structure including layers of conductive features embedded within respective layers of dielectric materials overlie the optical feature. The interconnect structure is patterned to remove the interconnect structure from over the optical feature and a dielectric material having optically neutral properties, relative to a desired light wavelength(s) is formed over the optical feature. One or more electronic ICs may be bonded to the optical IC to form an integrated package.

Methods of fabricating optical devices with high refractive index materials are disclosed. The method includes forming a first oxide layer on a substrate and forming a patterned template layer with first and second trenches on the first oxide layer. A material of the patterned template layer has a first refractive index. The method further includes forming a first portion of a waveguide and a first portion of an optical coupler within the first and second trenches, respectively, forming a second portion of the waveguide and a second portion of the optical coupler on a top surface of the patterned template layer, and depositing a cladding layer on the second portions of the waveguide and optical coupler. The waveguide and the optical coupler include materials with a second refractive index that is greater than the first refractive index.

Methods of fabricating optical devices with high refractive index materials are disclosed. The method includes forming a first oxide layer on a substrate and forming a patterned template layer with first and second trenches on the first oxide layer. A material of the patterned template layer has a first refractive index. The method further includes forming a first portion of a waveguide and a first portion of an optical coupler within the first and second trenches, respectively, forming a second portion of the waveguide and a second portion of the optical coupler on a top surface of the patterned template layer, and depositing a cladding layer on the second portions of the waveguide and optical coupler. The waveguide and the optical coupler include materials with a second refractive index that is greater than the first refractive index.

Structures for an optical coupler and methods of fabricating a structure for an optical coupler. A first waveguide core has a first tapered section and a second waveguide core has a second tapered section positioned adjacent to the first tapered section. The first tapered section has a first shape determined by a first non-linear function, and the second tapered section has a second shape determined by a second non-linear function.