Abstract: A serpentine delay-line waveguide feeding an array of grating couplers can be fabricated in a silicon photonic chip, or tile, with the grating couplers emitting light at an angle that varies with wavelength and delay between the couplers imparted by the waveguide. The beam-steering tile can be used to transmit or receive light from a scene. The tile can be arrayed with one or more other tiles for bistatic radar-lidar operation. A tile in the array may transmit probe and frequency-shifted reference beams, while another tile may receive a return at a heterodyne frequency giving a range to the scene. The pitch of the serpentine delay line may be different for transmitting and receiving tiles to suppress returns from unwanted directions. Pairs of phase-cohered tiles may illuminate a spot in the scene with fringe patterns, producing oscillating returns that can be processed to form a high-resolution sub-image by Fourier synthesis.

Abstract: Recent remarkable progress in wave-front shaping has enabled control of light propagation inside linear media to focus and image through scattering objects. In particular, light propagation in multimode fibers comprises complex intermodal interactions and rich spatiotemporal dynamics. Control of physical phenomena in multimode fibers and its applications is in its infancy, opening opportunities to take advantage of complex mode interactions. Various embodiments of the present technology provide wave-front shaping for controlling nonlinear phenomena in multimode fibers. Using a spatial light modulator at the fiber's input and a genetic algorithm optimization, some embodiments control a highly nonlinear stimulated Raman scattering cascade and its interplay with four wave mixing via a flexible implicit control on the superposition of modes that are coupled into the fiber.

Abstract: Recent remarkable progress in wave-front shaping has enabled control of light propagation inside linear media to focus and image through scattering objects. In particular, light propagation in multimode fibers comprises complex intermodal interactions and rich spatiotemporal dynamics. Control of physical phenomena in multimode fibers and its applications is in its infancy, opening opportunities to take advantage of complex mode interactions. Various embodiments of the present technology provide wave-front shaping for controlling nonlinear phenomena in multimode fibers. Using a spatial light modulator at the fiber's input and a genetic algorithm optimization, some embodiments control a highly nonlinear stimulated Raman scattering cascade and its interplay with four wave mixing via a flexible implicit control on the superposition of modes that are coupled into the fiber.

Abstract: A serpentine delay-line waveguide feeding an array of grating couplers can be fabricated in a silicon photonic chip, or tile, with the grating couplers emitting light at an angle that varies with wavelength and delay between the couplers imparted by the waveguide. The beam-steering tile can be used to transmit or receive light from a scene. The tile can be arrayed with one or more other tiles for bistatic radar-lidar operation. A tile in the array may transmit probe and frequency-shifted reference beams, while another tile may receive a return at a heterodyne frequency giving a range to the scene. The pitch of the serpentine delay line may be different for transmitting and receiving tiles to suppress returns from unwanted directions. Pairs of phase-cohered tiles may illuminate a spot in the scene with fringe patterns, producing oscillating returns that can be processed to form a high-resolution sub-image by Fourier synthesis.

Abstract: Recent remarkable progress in wave-front shaping has enabled control of light propagation inside linear media to focus and image through scattering objects. In particular, light propagation in multimode fibers comprises complex intermodal interactions and rich spatiotemporal dynamics. Control of physical phenomena in multimode fibers and its applications is in its infancy, opening opportunities to take advantage of complex mode interactions. Various embodiments of the present technology provide wave-front shaping for controlling nonlinear phenomena in multimode fibers. Using a spatial light modulator at the fiber's input and a genetic algorithm optimization, some embodiments control a highly nonlinear stimulated Raman scattering cascade and its interplay with four wave mixing via a flexible implicit control on the superposition of modes that are coupled into the fiber.

Abstract: Recent remarkable progress in wave-front shaping has enabled control of light propagation inside linear media to focus and image through scattering objects. In particular, light propagation in multimode fibers comprises complex intermodal interactions and rich spatiotemporal dynamics. Control of physical phenomena in multimode fibers and its applications is in its infancy, opening opportunities to take advantage of complex mode interactions. Various embodiments of the present technology provide wave-front shaping for controlling nonlinear phenomena in multimode fibers. Using a spatial light modulator at the fiber's input and a genetic algorithm optimization, some embodiments control a highly nonlinear stimulated Raman scattering cascade and its interplay with four wave mixing via a flexible implicit control on the superposition of modes that are coupled into the fiber.

Abstract: Techniques for analog processing of high time-bandwidth-product (TBP) signals use a material with an inhomogeneously broadened absorption spectrum including multiple homogeneously broadened absorption lines. A first set of signals on optical carriers interact in the material during a time on the order of a phase coherence time of the homogeneously broadened absorption lines to record an analog interaction absorption spectrum. Within a time on the order of a population recovery time for a population of optical absorbers it the material, the interaction absorption spectrum in the material is read to produce a digital readout signal. The readout signal represents a temporal map of the interaction absorption spectrum, and includes frequency components that relate to a processing result of processing the first set of signals. The techniques allow processing of RADAR signals for improved range resolution to a target, as well as speed of the target, among other uses.

Abstract: Techniques for analog processing of high time-bandwidth-product (TBP) signals use a material with an inhomogeneously broadened absorption spectrum including multiple homogeneously broadened absorption lines. A first set of signals on optical carriers interact in the material during a time on the order of a phase coherence time of the homogeneously broadened absorption lines to record an analog interaction absorption spectrum. Within a time on the order of a population recovery time for a population of optical absorbers it the material, the interaction absorption spectrum in the material is read to produce a digital readout signal. The readout signal represents a temporal map of the interaction absorption spectrum, and includes frequency components that relate to a processing result of processing the first set of signals. The techniques allow processing of RADAR signals for improved range resolution to a target, as well as speed of the target, among other uses.