Hughes Aircraft Company

Trw Limited

Other

Digital Signal Corporation

Digital Optronics Corporation

Frank E Goodwin

Anthony R Slotwinski

Thomas A Nussmeier

Ross E Graves

Charles B Morrison

Luis Figueroa

Bor-Uei Chen

Hans C Marciniak

Hsiang-Yi D Law

Michael S Hersman

Dana Simonson

A three-dimensional optical scanning vision system capable of producing high-resolution images in real-time includes an optical source for producing a source light beam. The source light beam is directed to a beam splitter which splits it into a local oscillator beam and a signal beam. The local oscillator beam is directed toward a photodetector, while the signal light beam is directed toward a target. Light reflected from the target is received by the beam splitter and directed toward a retroreflector which returns the beam to the beam splitter interface. Quarter wave plates and the retroreflector insure that the return light beam and the local oscillator beam are collimated and have the same polarization state. Mixing of the local oscillator beam and the return light beam occurs at the beam splitter interface, thus providing coherent optical detection by the photodetector. The photodetector thus provides an output signal providing a high degree of information about the target. The system also includes scanner optics to scan the signal light beam across the target. A processor is also included for outputting a three-dimensional image of the target, and for controlling the scanner optics.

3-Dimensional vision system utilizing coherent optical detection

An apparatus and a method for measuring the distance to an arbitrary target includes a radiation source producing a beam of coherent radiation the frequency of which is continuously varied. The beam is divided into a ranging beam and a reference beam. The ranging beam is coupled to a ranging interferometer, which directs a portion of the ranging beam at the target. The ranging interferometer produces a first signal indicative of the phase difference between a portion of the ranging beam directed at and scattered by the target and another portion of the ranging beam which has traveled over a path of fixed length. The reference beam is coupled to a reference interferometer. A portion of the reference beam is directed by the reference interferometer along a reference path of a predetermined length, and the phase difference between the portion of the reference beam directed along the reference path and another portion of the reference beam which has travelled over a path of a fixed length is measured. The number of fringes resulting from the wave interference produced in the ranging interferometer and the number of fringes in the wave interference pattern produced by the reference interferometer are counted and used, together with the known length of the reference path, to determine the distance of the target from the ranging interferometer.

Frequency modulated lasar radar

A laser proximity sensor for a projectile includes a laser diode having front and rear facets. The diode generates a main laser signal and directs a first portion thereof out of the front facet as a source beam. Focusing means focuses the source beam on a target, and focuses the return beam reflected from the target into the laser diode through the front facet. The laser diode receives the return light beam, provides it with a positive gain, mixes it with the main laser signal, and guides it out the rear facet as a mixed beam. A detection focusing device focuses the mixed beam onto a PIN detector. The PIN detector coherently detects the mixed beam and provides an output signal having a perturbation where the target enters the focal field of the focusing optics. A processor detects the output signal from the PIN detector and may activate a fuse on the projectile. The processor is also capable of determining the relative velocity between the projectile and the target from measurement of the Doppler shifted signal or from the shape of the perturbation of the output signal from the PIN detector.

Laser proximity sensor

A device for combining the outputs of multiple laser sources to produce a single coherent beam with good far-field characteristics. The device includes an optical star coupler having multiple path lengths that are deliberately chosen to be different, by amounts that give rise to an interference pattern that has constructive interference peaks at periodic cycles along a wavelength interval. The optical path-length differences result in the occurrence of at least one wavelength, within the operating range of the lasers, at which all of the lasers will operate. The relationships among the optical path lengths is such that the lasing wavelength is relatively insensitive to phase mismatches along the path lengths.

Laser combiner

A high pressure CO.sub.2 laser waveguide having an extended tuning range. The laser cavity is bounded by a first partially reflecting member and a second partially reflecting member, the second member comprising a reflecting mirror and a diffraction grating member used in the Littrow configuration, the grating being positioned outside the laser cavity and spaced from the second reflecting mirror a predetermined distance. The combination of the mirror and grating provides an effective grating reflectivity which is sufficient to extend the tuning range of the laser to a value not previously available.

RF-excited CO.sub.2 waveguide laser with extended tuning range

A semiconductor laser array structure operable at relatively high powers and high brightness levels compared with prior laser arrays. At least two principal lasing regions are formed in a single active layer of the structure, and are closely coupled by an intermediate region in which there is optical gain. Preferably, the dimensions of the structure are selected to provide single-filament lasing in the principal lasing regions and in the intermediate region, resulting in a composite output that is apparently phase-locked and has a high-brightness, single-lobe far-field radiation distribution pattern with a low divergence angle. The disclosed structure uses gallium arsenide and gallium aluminum arsenide materials and is fabricated using liquid-phase epitaxy. Longitudinal mode selection in the device may be accomplished by configuring the two channels to produce different sets of longitudinal modes, the close coupling of the two regions resulting in the output of only those modes common to both regions.

Semiconductor laser structure

An improved homodyne receiver for use in wideband optical communications systems is disclosed. The receiver utilizes quadrature demodulation of the optical signal in the manner of a two-phase receiver. A beam-splitting/phase-splitting optical assembly is used to channelize the received and the local oscillator beams to a pair of optical detectors. Squaring amplifiers in the quadrature channels followed by a summing network provide an output signal which is proportional to the square of the modulation of the input signal. This receiver is especially well-suited to the reception of Pulse Code Modulated optical signals.

Dual channel optical homodyne receiver

An improved homodyne receiver for use in wideband optical communications systems is disclosed. The receiver utilizes dual channelization of the optical input signal in the manner of a Costas two-phase synchronous receiver. A novel beam-splitting/phase-splitting optical assembly is used to channelize the received and the local oscillator beams and insure the desired phase relationships. The receiver is capable of phase-locked operation in the presence of noise and frequency variations in the received and local oscillator signals.

Growing community of inventors

Burke, VA, United States of America

Frank E Goodwin