Abstract: In a light raster scanning system imaging a medium located on a movable stage and using bidirectional scanning, i.e. scanning during stage movement in two opposing directions, the problem of chevron artifacts (angle errors), due to the different stage movement directions, is overcome by a system of reflective optics including two optical elements dynamically movable relative to one another. One of the optical reflective elements is tilted or rotated relative to the other to compensate for the angle error causing the chevron artifacts. The amount of this tilt is dynamically altered depending on the direction of stage travel and also may be dynamically adjusted to maintain linearity of the scan pattern in spite of any other irregularities in stage velocity. Also an autofocus feature is provided, whereby the two reflective elements are moved relative to one another to dynamically alter the focus of the light beam onto the medium and hence overcome any defocus problems due to irregularities in the medium surface.

Abstract: Two axes laser interferometers are well known for determining the XY position of a stage, for instance for photolithography equipment. Each of the X and Y coordinates is measured to great precision by reflecting a laser beam from a long flat mirrored surface lying perpendicular to the axis of interest. Instead of using a single one-piece mirror having two reflective surfaces, three mirrors are provided in the configuration of two independent rigid bodies; there are two extended main mirrors each of which is formed on a separate optical element and a third smaller calibration mirror which is fabricated at a right angle at the end surface of one of the long mirrors or is adhesively bonded or held mechanically thereto. The angular relationship between the calibration mirror and the mirror to which it is attached is rigid and the orthogonality error is calibrated and recorded. This calibration mirror is a reference surface for the second elongated mirror to which it is nominally parallel.

Abstract: An acoustical phased array having improved interaction efficiency and efficiency-bandwidth product. The array includes a body of acousto-optical material having one face grooved to form a number of sets of plane parallel surfaces, each set having n different height levels, where n is at least two. An electro-acoustic transducer is affixed to each surface and high-frequency signals are applied to the respective sets of transducers, each signal being phase-displaced by the same amount with respect to the signal applied to an adjacent set. The incremental height difference is 1/n of the phase difference between signals applied to adjacent sets, expressed in wavelengths, and this results in elimination of one lobe of what would otherwise be a twin-lobe far-field acoustic radiation pattern, and an approximate doubling in interaction efficiency.

Abstract: A system for remote measurement of structural forces includes a plurality of microbend transducers mounted along the length of the structure for microbending an optical fiber in response to structural forces, such as stress acting upon an oil or gas pipeline or the like. An optical time domain reflectometer (OTDR) has a light source for launching a pulsed optical signal for passage through the fiber and a photodetector for sensing as a function of time the intensity of backscattered light reflected back through the fiber, wherein this sensed time function is correlated directly with discrete longitudinal positions along the length of the fiber and the structure. When one or more of the microbend transducers is activated to induce a microbend in the fiber in response to localized forces acting upon the structure, a portion of the backscattered light is lost at the microbend. This attenuation in backscattered light intensity is sensed quantitatively and positionally identified by the photodetector.

Abstract: A system for remote measurement of structural forces includes a plurality of microbend transducers mounted along the length of the structure for microbending an optical fiber in response to structural forces, such as stress acting upon an oil or gas pipeline or the like. An optical time domain reflectometer (OTDR) has a light source for launching a pulsed optical signal for passage through the fiber and a photodetector for sensing as a function of time the intensity of backscattered light reflected back through the fiber, wherein this sensed time function is correlated directly with discrete longitudinal positions along the length of the fiber and the structure. When one or more of the microband transducers is activated to induce a microbend in the fiber in response to localized forces acting upon the structure, a portion of the backscattered light is lost at the microbend. This attenuation in backscattered light intensity is sensed quantitatively and positionally identified by the photodetector.

Abstract: A system for remote measurement of structural forces includes a plurality of microbend transducers mounted along the length of the structure for microbending an optical fiber in response to structural forces, such as stress acting upon an oil or gas pipeline or the like. An optical time domain reflectometer (OTDR) has a light source for launching a pulsed optical signal for passage through the fiber and a photodetector for sensing as a function of time the intensity of backscattered light reflected back through the fiber, wherein this sensed time function is correlated directly with discrete longitudinal positions along the length of the fiber and the structure. When one or more of the microbend transducers is activated to induce a microbend in the fiber in response to localized forces acting upon the structure, a portion of the backscattered light is lost at the microbend. This attenuation in backscattered light intensity is sensed quantitatively and positionally identified by the photodetector.

Abstract: A system for remote measurement of structural forces includes a plurality of microbend transducers mounted along the length of the structure for microbending an optical fiber in response to structural forces, such as stress acting upon an oil or gas pipeline or the like. An optical time domain reflectometer (OTDR) has a light source for launching a pulsed optical signal for passage through the fiber and a photodetector for sensing as a function of time the intensity of backscattered light reflected back through the fiber, wherein this sensed time function is correlated directly with discrete longitudinal positions along the length of the fiber and the structure. When one or more of the microbend transducers is activated to induce a microbend in the fiber in response to localized forces acting upon the structure, a portion of the backscattered light is lost at the microbend. This attenuation in backscattered light intensity is sensed quantitatively and positionally identified by the photodetector.

Abstract: An optical system including a radio frequency signal input; a chirp signal input; a source for emitting a beam of radiation; an acousto-optical modulator disposed in the path of the beam and functioning to modulate the beam with the radio frequency signal and the chirp signal to produce a modulated beam; and a single detector disposed in the path of the third modulated beam. The inventor further provides electronic alignment and focusing by changing the chirp frequency.

Abstract: An optical system for performing a cosine transform on an input RF signal is described. The optical system includes a source for emitting a beam of radiation, and an acoustic-optical modulation device disposed in the path of the beam and functioning to modulate at least two spaced-apart spatial portions of the beam with different signals to produce two modulated beams.A Fourier transfer lens is provided which is disposed in the path of the two modulated beams for combining the two beams, and a detector is disposed in the path of the Fourier transform beam at the focal plane of the Fourier transfer lens.

Abstract: An acoustic wave device wherein each electrode element of an interdigital transducer is buried or embedded between a pair of layers of piezoelectric material. The use of a multi-layer stack of layers of piezoelectric material enables each electrode element of the transducer to be sandwiched between a distinct pair of layers and thus to be insulated from the other electrode element or elements. Because of the insulation thus provided, the spacing between the fingers of each electrode element may be selected without fear of causing short circuits between electrode elements.

Abstract: An optical system including a radio frequency signal input; a chirp signal input; a source for emitting a beam of radiation; a first acousto-optical modulator disposed in the path of the beam and functioning to modulate the beam with the radio frequency signal to produce a first modulated beam; a second acousto-optical modulator disposed in the path of the first modulated beam to modulate the beam with the chirp signal to produce a third modulated beam; and a single detector disposed in the path of the third modulated beam.

Abstract: A CCD driven integrated optical modulator array including an array of chirp grating optical lenses implemented on the surface of an electro-optical crystal such as LiNbO.sub.3 or LiTaO.sub.3, a plurality of channel waveguides and a thin metal film pattern on the surface of the waveguides for modulating the optical waveform in each channel. The thin metal film form planar capacitors, each of the capacitors being electrically connected to the output circuit of a corresponding semiconductor device, such as a CCD array. The CCD array is implemented on a semiconductor wafer bonded to the electro-optical crystal. Signals in each optical channel in the electro-optical crystal are thereby modulated by corresponding circuit elements associated with corresponding CCD channels implemented on the major surface of the semiconductor wafer.

Abstract: A Sagnac interferometer gyroscope includes a semiconductor chip on which is formed an optical waveguide. Means are provided on the optical waveguide to inject a laser light beam into the waveguide and onto a divider to produce first and second divided beams. Second and third dividers are provided in the waveguide to generate a reference signal onto a pair of photodectors disposed to receive the divided light waves. The light waves are modulated with first and second frequencies prior to their second division by a pair of Bragg frequency shifter interdigital transducers. The divided and modulated light beams are then directed through an optical path encompassing an axis of sensitivity of the gyro. In one embodiment the path is formed by an optical fiber with connections to the chip. In another embodiment the optical path is defined within the chip itself by reflectors or deflectors at selected locations about the peripheral of the chip.

Abstract: A high-throughput diffraction-limited Bragg diffraction grating having a variable periodicity functions as a lens for optical guided waves. The lens may be fabricated with planar photolithograhic techniques. It has predictable focusing properties which are insensitive to process variations making it particularly useful for mass production of integrated optical systems.

Abstract: A digital-to-analog optical recorder incorporating both CCD and integrated optics technologies which is fabricated as a single integral unit including an electro-optical layer portion and a semiconductor layer portion. Sampling circuits and digital-to-analog converters are implemented on the semiconductor layer portion using CCD technology, and a plurality of optical channel waveguides and electro-optical modulators are implemented on the electro-optical layer portion. Each digital signal is converted into two complementary light spots at the output of the recorder.

Abstract: An interferometer gyro employing a coiled optical fiber includes a pair of acousto-optic modulators to modulate first and second frequencies onto two components divided from the light of a light source. The light source need not exhibit the high degree of source coherence heretofore required, and can be an incandescent bulb in many applications. The first and second modulated light components are injected in opposite or counter-rotating directions into the optical fiber wherein they experience phase changes due to the apparent change in optical length of the optical fiber upon rotation of the fiber about an axis of sensitivity. The light components are then, after being removed from the fiber, combined and compared with the signals applied at the input. The phase difference therebetween is then established to measure the rate of rotation of the optical fiber about the axis of sensitivity.

Abstract: A method of fabricating a stepped-array acousto-optic beam deflector comprising the steps of providing a substrate having upper and lower surfaces lying in mutually oblique planes, forming an electro-acoustic transducer on the upper substrate surface, cutting through the substrate and the upper and lower surfaces to form a plurality of disjoined transducer elements positioned side by side, and mounting the disjoined transducer elements in tandem to an acousto-optic element.

Abstract: A low loss optical waveguide is provided by taking a silicon substrate with a silicon dioxide waveguide thereon and depositing lead on the air interface surface of the silicon dioxide. The lead is then oxidized and diffused into the silicon dioxide creating a high optical quality, high index region at the air interface of the waveguide. This allows transmitted waveguide light energy directed into the silicon dioxide to be transmitted in the lead oxide diffused portion of the waveguide, keeping the energy away from the lossy silicon substrate, and thereby providing a low loss planar waveguide.