Acousto-optic signal processors for transmission and reception of phased-array antenna signals

Novel acousto-optic processors for control and signal processing in phased-array antennas are presented. These processors can operate in both the antenna transmit and receive modes. An experimental acousto-optic processor is demonstrated in the laboratory. This optical technique replaces all the phase-shifting devices required in electronically controlled phased-array antennas

Digital Control Polarization Based Optical Scanner

High speed low cost billion point optical scanner using a binary optical polarization sensitive cascaded architecture network having binary switchable optical plates for scanning in one dimension(x-direction), two dimensions(x and y directions) and three dimensions(x, y and z directions). The scanner has a fast microsecond beam switching speed and low control power and realizes high space bandwidth products of up to one billion points using minimum control signals and hardware. The binary switching optical plates are modules for the x, y, and z directions. For each of the directions, each module contains an active polarization switches and passive beam steering devices. The switches can be high speed flat panel thin film polarization switches such as ferroelectric liquid crystal devices or multiple quantum well binary polarization rotation devices or nematic liquid crystal(NLC) polarization rotator devices. The beam steering devices can be birefringent plates such as birefringent mod

Hybrid Photonic Signal Processing Modules

Proposed are designs for a new kind of switchless variable optical delay line module for signal processing that combines an analog controlled and implemented variable optical delay line with a digital discrete state variable optical delay line. This hybrid design uses smart wavelength tuning of a laser in combination with spatially and temporally dispersive optical elements to provide both long time delays and short time delays covering a wide dynamic range of delays. The proposed designs can also intrinsically provide variable optical attenuation control for the input light signals. The proposed variable delay lines can be used for Radio Frequency (RF) and digital electrical signals requiring time delay and amplitude processing such as in programmable RF filters and optically controlled RF phased array antennas and radars. The proposed modules can also be used in all-optical signal processing for communications and security systems

Hybrid Optical Distance Sensor

Methods and systems for hybrid optical sensor designs for high dynamic range high resolution remote distance or level measurements. The preferred sensor design uses a hybrid digital-analog controlled variable focal length lens system to target both specular (retro-reflective) and diffuse objects. Spatial image processing via an optical imager of direct (specular) or indirect (scattered) light is deployed to enable target path length measurement. An alternate sensor design combines the preferred spatial processing sensor design with time-frequency processing optical distance measurement methods to enable a robust hybrid-technique sensor. These sensor designs allows remote sensing of object distance, object motion displacement, object three dimensional structure, object spatial profile, and measurement of liquid levels, and different matter(gas-liquid, solid-gas, liquid A-liquid B) interface positions

Scanning heterodyne Acousto-optical interferometers

Compact, high performance, scanning heterodyne optical interferometers for interferometric phase-based measurement and a host of other applications are introduced. An in-line, almost common-path optical interferometer design offers robustness to externally induced phase noise via mechanical vibrations, thermal effects, and other environmental effects. Several instrument designs are disclosed for both transmissive and reflective interferometry. These interferometers use acousto-optic devices or Bragg cells to implement rapid (e.g., \u3c50 \u3e.mu.s/scan spot) optical scanning of a test medium. Although the read optical beam scans a given test region, the double Bragg diffraction optical design of the instrument makes the final interfering output beams stationary on the two high speed photo-detectors used for radio frequency signal generation via heterodyne detection. One photo detector acts as the fixed phase reference, while another fixed photo detector picks up the test medium phase informa

Compact Optical Controller for Phased Array Systems

A compact free-space/solid optics phased array antenna/transducer optical controller is disclosed that uses the principle of in-phase (I) and quadrature (Q) vector modulation via two dimensional (2-D) spatial light modulators (SLMs). The SLMs are used as distributed optical gain/amplitude control devices. The system can be fed by four independent lasers where one pair of lasers must be mutually incoherent (or their beat frequency is not in the interested spectrum) with the other pair of lasers. These lasers are modulated (directly or externally) by separate forms (different phase shifts: 0, 90, 180, 270) of the input source signal/modulated radio frequency (rf) carrier. Each of the four different sets of light beams (each set containing N light beams; N=Total antenna/transducer elements in phased array) is independently amplitude modulated by the 4X N modulating pixels of the SLM. Depending on the phase and amplitude of the carrier required on the nth antenna/transducer element, lase

Methods and Systems for Realizing High Resolution Three-Dimensional Optical Imaging

Methods and systems for realizing high resolution three-dimensional (3-D) optical imaging using diffraction limited low\u27 resolution optical signals. Using axial shift-based signal processing via computer based computation algorithm, three sets of high resolution optical data are detennined along the axial (or light beam propagation) direction using low resolution axial data. The three sets of low resolution data are generated by illuminating the 3~D object under observation along its three independent and orthogonal look directions (i.e., x. Y. and z) or by physically rotating the object by 90 degrees and also flipping the object by 90 degrees. The three sets of high resolution axial data is combined using a unique mathematical function to interpolate a 3-D image of the test object that is of much higher resolution than the diffiaction limited direct measurement 3-D resolution. Confocal microscopy or optical coherence tomography (OCT) are example methods to obtain the axial scan data sets

Switchless hybrid analog-digital variable optical delay line for radio frequency signal processing

The author proposes the design of a novel switchless variable optical delay line (VFODL) for radio frequency (rf) signals that combines an analog mode VFODL with a discrete-state VFODL. This hybrid VFODL proposes the use of a laser with smart, fast (e.g., 1 ns) wavelength tuning in combination with flat-top passband design spatially and temporally dispersive optical elements to simultaneously provide both long and short time delays, thus finely covering a wide nanoseconds delay range. An example design indicates a 9.6-ns time delay range with 6-ps increments, giving 1600 independent delays using a no-moving-parts signal-processing structure. VFODL applications include rf antenna array processing, radar testing, and precision electrical timing systems

Demonstration of three dimensional imaging of blood vessel using a no moving parts electronic lens-based optical confocal microscope

To the best of our knowledge, for the first time, biological Three Dimensional (3-D) imaging has been achieved using an electronically controlled optical lens to accomplish no-moving parts depth section scanning in a modified commercial 3-D confocal microscope. Specifically, full 3-D views of a standard CDC blood vessel (enclosed in a glass slide) have been obtained using the modified confocal microscope operating at the red 633 nm laser wavelength

Liquid crystal agile photonics: from fiber to the free-space domain

Liquid Crystals (LC) are excellent low loss large area programmable materials for smart optical device design leading to agile photonics. This paper describes work by the Riza group to enable intelligent system design from the fiber-optic realm to the freespace optics domain of applications. Specifically, novels works will be described in fiber-optic attenuator design, freespace optical scanners, fiber-optic switches, fiber-optic delay lines, and laser beam profilers. Both theory and experimental demonstrations will be highlighted