Abstract: A gyroscope which utilizes light waves to sense motion in the plane of the substrate. The gyroscope has a primary optical waveguide which is adapted to pass light from a single light source through the primary optical waveguide in both directions. The light exiting from each end of the primary optical waveguide is withdrawn and passed through two dedicated waveguides (one dedicated waveguide for each end of the primary optical waveguide). Preferably, these two dedicated waveguides have differing times for light travel such that one of the dedicated waveguides emits its light one-quarter wavelength behind the other dedicated waveguide. The light being emitted from each dedicated waveguide is then combined permitting a sensor to monitor any shifts between the two light signals as a monitor to motion of the primary optical waveguide.

Abstract: A fiber optic interferometric sensor (150) having constantly high sensitivity by use of two lasers (152, 154) that simultaneously output at first and second wavelengths. By judicious choice of the wavelengths, the optical path length difference between the two interferometer paths (164, 166) can be kept near the maximum slope of the interference fringes for one or the other of the wavelengths. The output from the interferometer (160) is divided between first and second detector arms (170, 130). A filter (172) in the first detector arm passes the first wavelength and rejects the second. A filter (182) in the second detector arm passes the second wavelength and rejects the first. A first detector (174) at the output of the first detector arm reads the interference pattern at the first wavelength. A second detector arm reads the interference pattern at the second wavelength.

Abstract: A sensor, an optical accelerometer, which is sensitive enough for the measurement of nano-g's as well as thousands of g's. The sensor is created by an optical waveguide coil which is secured to a substrate. At one end of the waveguide coil, a mirror reflects the emitting light back into the waveguide coil. Positioned along one side of the substrate, a proof mass is adapted to exert force against and deform the optical waveguide coil during acceleration of the sensor. An identical optical waveguide coil is secured to the opposing side of the substrate with its associated proof mass positioned on the side of the substrate opposite the other side's proof mass. A beamsplitter communicates light into the ends of the two waveguide coils and then a monitor uses the light being emitted from the ends of the coils to measure the g's being applied.

Abstract: A measurement optical fiber is placed into contact with a geological structure, and a reference optical fiber of about the same length is not contacted to the geological structure. An input beam of light is transmitted down the lengths of the measurement and reference optical fibers, and the interference fringes formed between the reflected beams in the two optical fibers are counted to determine the geological displacement, and thence the geologic strain, experienced by the measurement optical fiber. Preferably, multiple pairs of the measurement and reference optical fibers are used, the optical fibers of the various pairs being of different lengths. The difference in displacement measured by any two pairs is a measure of the geological strain in the region between the ends of the two pairs. The multiple pairs are conveniently provided in two optical fiber cables, a measurement cable which contacts the geological structure and a reference cable which extends parallel and adjacent to the measurement cable.

Abstract: An array of acoustic signal sources and sensors are positioned in a fluid. Acoustic signals propagated through the medium are subjected to phase differences as they pass through fluid currents. An eikonal description of the acoustic waves propagating through the fluid medium is used to derive the fluid currents. Fluid currents are measured in a multiplicity of acoustic paths extending from the acoustic sources to the sensors, using acoustic phase tomography.

Abstract: An improved image transmission system which includes an elongate optical waveguide 15 having an input aperture 17 and an output aperture 19. Optical apparatus 11, 13 is provided for injecting a transform of an image into the waveguide. In a specific implementation, the Fourier transform of the image is injected at the input aperture 17. The output image is transformed as well to provide the desired image. When the Fourier components of the image are transmitted, each component propagates at a different velocity. However, the magnitude of the components are preserved and used to reconstruct the image at the output of the waveguide. This allows for the transmission of optical images without digitization with a single, inexpensive waveguide.

Abstract: An optical fiber disposed to partially internally reflect optical energy passing therethrough is disclosed herein. The optical fiber 10 of the present invention includes an internal partial mirror disposed to partially transmit and to partially reflect optical energy incident thereon. The internal mirror is effectively realized at an interface I of first and second fiber segments 14 and 18. The first fiber segment 14 includes a first core region 22 which circumscribes a longitudinal axis X. The first core region 22 is of a first cross-sectional area perpendicular to the longitudinal axis X. The inventive fiber 10 further includes a second fiber segment 18 in optical communication with the first fiber segment 14. The second fiber segment 18 includes a second core region 24 which circumscribes the longitudinal axis X, wherein the second core region 24 is of a second cross-sectional area perpendicular thereto.

Abstract: A sensitive towed optical fiber sensor array 50, wherein the fiber sensors (60A-60N) are connected in parallel, and the optical fiber cable (34) is paid out from the towing ship at a velocity about equal to but opposite to the velocity of the towing ship. The fiber sensors (60A-60N) are immune to electromagnetic interference, and the output of the sensors can be isolated readily to the parallel hookup of the sensors. Turbulence and acceleration noise is greatly reduced due to the manner in which the fiber cable (34) is paid out, and crosstalk between sensors is eliminated.

Abstract: An optical fiber evanescent wave fuel sensor, employing a light source with a wavelength selected to be at the strong infrared absorption lines of the fuel, typically hydrocarbons. The amount of light leaking from the optical fiber is an exponential function of the length of the fiber in the liquid, and is independent of the relative indices of refraction of the fuel and fiber cladding material.

Abstract: A nondestructive method and apparatus is disclosed for determining the thickness and composition of a zinc phosphate layer applied to a metal surface, such as sheet metal on an automotive assembly line. The phosphate layer is irradiated with infrared light which is at least partially transmitted through the phosphate layer. Reflections from the upper and lower surfaces of the phosphate layer return a total reflected intensity which is a function of the optical parameters of the phosphate components and the ratio of the components corresponding to the optical parameters. In the event, for example, that a phosphate layer includes two zinc phosphate components, the measure of reflected intensity at two separate wavelengths will be different inasmuch as the optical properties of the zinc phosphate components is also a function of frequency.

Abstract: A system for washing the air in a coastal environment in which a volume of air moves from a land mass to a water mass. The system includes a plurality of fountains 12 mounted offshore which spray a volume of water into the path of the air flow. Water is stored under pressure and selectively released to form the spray. In specific embodiments, wave motion is used to provide the power to pressurize the stored water. Wave power is extracted by dual reciprocating pumps 50 and 51 connected to a float 40. Wave power is amplified by lenses 20 which focus the waves onto the floats 40. A control system 100 senses pollution and controls the generation of the spray. In addition, wave motion is sensed and used to control the position of the lens 20 for optimum performance and minimum wear.

Abstract: A system adapted for attachment to a device that undergoes changes in temperature and pressure, and for detecting changes in temperature and pressure in the device comprises a mechanism for attaching the system to the device and an optic device that includes pressure-responsive, temperature-responsive optical fibers that produce signals representative of temperature changes over a first optical frequency band, and of pressure changes over a second, distinctly different optical frequency band, or two or more optic devices, at least one including a pressure-responsive optical fiber, and at least one including a temperature-responsive optical fiber.

Abstract: An evanescent wave liquid level sensor for measuring the density-compensated level of a liquid in a container. The sensor employs an eccentric core optical fiber fully immersed in the liquid to be measured. Light is injected into one end of the fiber. Some of the light will be lost due to evanescent wave losses. Changes in the ratio of the intensity of the input light and the reflected light are due solely to changes in the density of the liquid. Changes in the liquid density can then be used to compensate a liquid level measurement. Since the liquid temperature is related to its density, the sensor can also be used to measure changes in the liquid temperature.

Abstract: Optical phased arrays employing a large number of light emitters and optical phase delays between adjacent emitters to steer and focus an optical beam from the contributions of all the light emitters. The array can include a laser oscillator (22) as the light source, with the laser light being conducted via optical waveguides (26, 30 and 32) into optical fibers (34), with phase delays being effected by piezoelectric or electro-optic effects on the optical waveguides. The array can be used in a low cost display device for generating optical images or in an optical memory.

Abstract: An eccentric core optical fiber 10 having a cross-sectional area sufficiently large to afford ease of manipulation, yet deposed to operate in an evanescent mode, is disclosed herein. The inventive optical fiber 10 includes a fiber core 20 of a first index of refraction. The fiber core 20 circumscribes a first longitudinal axis. The optical fiber 10 of the present invention further includes fiber cladding material 30 of a second index of refraction chosen to be less than the first index of refraction. The cladding material 30 circumscribes both a fiber core 20 and a second longitudinal axis oriented parallel to but not coincident with the first longitudinal axis.

Abstract: This invention discloses a method and apparatus for shortening the length of a pulse of light. Generally, the method entails altering the index of refraction of an optical medium (14) through which the pulse of light is traveling at an area of the medium (14) where the front end of the pulse of light is located, such that the front end of the pulse of light travels slower than the back end, thus enabling the back end to catch up with the front end in order to shorten the length of the pulse. To accomplish this, it is proposed to generate an electric field across the optical medium (14) by a charge carrying medium (12) positioned relative to the optical medium (14), such that the index of refraction is altered by the electro-optic effect.

Abstract: A fiber optic fuel or liquid level gauge is disclosed which determines the liquid level by measuring the amount of light loss due to evanescent transfer to the fuel or liquid. An optical fiber is supported in the fuel or liquid tank, with a first end adjacent the highest possible liquid level to be measured with a reflector at the first end. The optical fiber extends downwardly through the tank, and its second end is connected to a light source for injecting light into the fiber. The intensity of the input light is compared to the intensity of light reflected from the first fiber end, and the liquid level is calculated from the light loss. The gauge has very high reliability since it has no moving mechanical parts.

Abstract: An adaptive electroopical lens system for use in optical data storage systems, optical phased arrays, laser or other optical projectors, and raster scanning devices, and the like. The invention provides an electrooptical means for scanning an optical beam or moving an optical storage or retrieval point. Beam movement is achieved electrooptically, by changing the index of refraction of an electrooptical material by controlling electric fields applied thereto. A plurality of electrodes are disposed on one surface of the electrooptic material and a ground electrode is disposed on the other. The electrodes are adapted to apply electric fields derived from a voltage source to the electroopic material that selectively change its index of refraction and provides for a predetermined index of refraction profile along at least one dimension thereof, thus forming a lens. By appropriately forming the electrode pattern and properly controlling the voltages applied thereto, differing lens shapes may be formed.

Abstract: A dislocation-free, composite-substance crystal having a lattice constant which decreases over the length of the crystal (38) convergently focuses beams of hard X-rays or gamma rays (11). A single-substance, dislocation-free crystal (34) collimates diffuse beams of hard X-rays or gamma rays and projects the collimated radiation (11') to the focusing crystal (38). A mask (36) is interposed between the collimating crystal (34) and the focusing crystal (38) causing the collimated radiation (11'') to carry an image of the mask (36). The focusing crystal (38) produces a convergent hard X-ray beam or gamma ray beam (11''') to focus a reduced image of the mask (36) upon the photosensitive layer (41) of a wafer (39). An example of a dislocation-free crystal having a lattice constant which decreases over its length (38) is a dislocation-free silicon-germanium crystal (20) wherein the proportion of germanium to silicon varies over the length of the crystal.

Abstract: A sensor for detecting the presence of a particular chemical by determining the absolute frequency shift in the oscillating frequency of an antibody-coated oscillator. Specific antibodies deposited on a high Q crystal oscillator detect the change in frequency as chemical particulates become trapped by the antibodies and change the effective mass of the crystal. In one embodiment, two oscillating crystals are used, one that has been coated with the antibodies, and one that is uncoated. This permits detection of frequency differences between the oscillating frequencies of the two crystals, thus eliminating pressure, temperature, and humidity corrections that conventionally must be made. The sensor maintains a high specificity by using antibodies that are specifically related to the chemical to be detected, while achieving relatively good sensitivity by using high Q oscillators, such as quartz or sapphire, and eliminating drift problems due to temperature, pressure, and humidity.