A beam steering device includes a substrate with a first refractive index that defines a cavity, an electroactive material in the cavity that has a variable refractive index, and two sets of opposing overlays. The overlays in one set of opposing overlays are parallel to each other, while the overlays in the other set are tilted with respect to each other. This allows one or more electric fields between the overlays to be used to align the electroactive material in two different directions to change its refractive index, allowing for a faster speed of beam steering through refraction than conventional approaches.

Disclosed is an array antenna which is capable of shifting a phase of light. According to one aspect of the present exemplary embodiment, an optical phase shifting array antenna includes: a receiving unit configured to distribute input light to a plurality of antenna element waveguides; a phase shifting unit configured to shift a phase of light propagated to each antenna element waveguide by applying heat to each antenna element waveguide; an output unit including a plurality of antenna elements, and configured to output the light, which is propagated to each antenna element waveguide after a phase is varied in the phase shifting unit, to each antenna element; and a base part configured to seat the receiving unit, the phase shifting unit, and the output unit.

A communication system includes an antenna assembly. The antenna assembly includes an optical communication layer including a plurality of electro-optical (EO) antennas for communicating via an EO signal and a radio-frequency communication layer including a plurality of radio frequency (RF) antennas for communicating via an RF signal. A processor operates the antenna assembly to communicate via one or both of the EO signal and the RF signal.

An optical phased array (OPA) radiator includes a plurality of unit radiators configured to serve as optical waveguides, each of the unit radiators being made of a silicon material and each having a predetermined length, where the unit radiators are disposed in parallel; a cladding portion configured to cover the plurality of unit radiators; and a plurality of electrodes arranged in parallel with the plurality of unit radiators on the cladding portion, where the plurality of electrodes are arranged so as not to overlap the plurality of unit radiators in a vertical direction. A beam radiated through the unit radiators using a phased array can be efficiently vertically steered.

Methods, apparatus, devices, and systems for displaying three-dimensional objects by individually diffracting different colors of light are provided. In one aspect, an optically diffractive device includes: first and second diffractive components and a color-selective polarizer therebetween. The first diffractive component is configured to diffract a first color of light in a first polarization state incident at a first incident angle with a first diffraction efficiency at a first diffracted angle, and diffract a second color of light in a second polarization state with a diffraction efficiency substantially less than the first diffraction efficiency. The color-selective polarizer is configured to rotate the second polarization state of the second color of light to the first polarization state. The second diffractive component is configured to diffract the second color of light in the first polarization state with a second diffraction efficiency at a second diffracted angle substantially identical to the first diffracted angle.

Methods, apparatus, devices, and systems for displaying three-dimensional objects by individually diffracting different colors of light are provided. In one aspect, a system includes a display having a plurality of display elements and an optical device including at least two beam expanders configured to expand an input light beam in at least two dimensions to generate an output light beam to the display by diffracting the input light beam to adjust a beam size of the input light beam in the at least two dimensions, the input light beam including a plurality of different colors of light.

A communication system includes an antenna assembly. The antenna assembly includes an optical communication layer including a plurality of electro-optical (EO) antennas for communicating via an EO signal and a radio-frequency communication layer including a plurality of radio frequency (RF) antennas for communicating via an RF signal. A processor operates the antenna assembly to communicate via one or both of the EO signal and the RF signal.

A method and apparatus are provided for controlling the phase shifts produced in a binary corporate tree network of the kind, e.g., that can drive a phased array for steering an optical beam. The method employs a novel phase-wrapping technique in which an entire layer of the binary tree is disabled when the phase added in that layer reaches 2π. With that technique, it is possible to economize on electrical control lines and on the use of electric power, while still maintaining the ability to produce arbitrary phases at the output of the tree network.

Additive manufacturing systems and related methods are disclosed. In some embodiments, an additive manufacturing system includes a build surface, one or more laser energy sources configured to emit laser energy, an optical phased array operatively coupled to the one or more laser energy sources, and a Risley prism assembly comprising a plurality of wedge prisms. The optical phased array includes one or more phase shifters operatively coupled to the one or more laser energy sources and configured to control a phase of the laser energy. The optical phased array is configured to direct the laser energy towards the Risley prism assembly, and the Risley prism assembly is configured to direct the laser energy towards the build surface.

Time delay devices for producing tunable time delays in optical signals. Cascades of the time delay devices can be used for beam steering in phased-array antennas. The time delay may be produced by selecting a time delay between an input and output of the time delay device from any of the time delay obtained by all four-port switches of the time delay device being in an OFF state and time delays obtainable by switching any one of the four-port switches to an ON state; and producing the selected time delay between the input and output of the time delay device by performing any of avoiding an application of an electrical control signal to any of electro-optic switch elements of the time delay device and applying the electrical control signal to one of the electro-optic switch elements that corresponds to a four-port coupler corresponding to the selected time delay.