Excel Precision Corporation

Fibera, Inc.

Other

John C Tsai

David W Wang

Erica Tsai

Hubert Song

Joseph A Methe

Pey Schuan Jian

Guang-Yao Yan

Mervyn L Hopson

Jean Chi

Peiti Su

Kam-Fung Yan

Mao Wang

Mervyn I Hopson

A position determining system (PDS)() or multiple parameters measurement system (MPMS)() particularly useful for translation and rotation measurement of objects having up to five degrees of freedom. A light source () provides light beams () into at least two channels. Each channel may include an interferometer (), reflective target (), beam splitter (), detector (), and receiver (). In concert, the detectors () sense horizontal, vertical, and roll position and the receivers () sense longitudinal and yaw position change. Optionally, modulation can be imposed on the light beams () and phase-sensitive synchronous demodulation used to enhance accuracy.

Rotation and translation measurement

A data distribution system () including an information card () to work with a reader (). The information card () includes visible indicia () on its front, stripe zones () and a ring zone () nominally 'on' its back and a radio-frequency identification (RFID) tag (). The zones () are suitable for magnetically recording and the RFID tag is suitable for electronically storing data. Optional characteristics for such data can concurrently be recorded or stored. The reader () may be a linear reader (), a rotary reader (), a card-stationary reader (), or a RFID reader/interrogator (), and may optionally act automatically in response to reading one or more of the optional data characteristics. If the reader () is a rotary reader () the information card () may particularly be loaded into a cartridge () which is loaded into the rotary reader ().

Information card system

A hazard mitigation system to detect an object in a highway-railway grade crossing. A structure is provided that includes a fixed foundation and a surface layer that is cushionably placed above the foundation, such that the structure is located between tracks at the crossing. At least one sensor is mounted between the surface layer and the foundation. This sensor senses the weight of the object upon the surface layer and provides a sensor signal representative of that weight. A control unit receives the sensor signal, processes it to determine whether the object represents a potential hazard, and, if so generates a warning signal. The sensor can particularly include a pressure or strain gage, or a fiber optic sensor. When a fiber optic sensor is employed, it can particularly include a fiber Bragg grating.

Highway-rail grade crossing hazard mitigation

A hazard mitigation system to detect intrusion by an object into a track zone at a train station platform. A structure is provided that includes a fixed foundation and a surface layer that is cushionably placed above the foundation, such that the structure is located in the track zone. At least one sensor is mounted between the surface layer and the foundation. This sensor senses the weight of the object upon the surface layer and provides a sensor signal representative of that weight. A control unit receives the sensor signal, processes it to determine whether the object represents a potential hazard, and, if so generates a warning signal. The sensor can particularly include a strain or pressure gage, or a fiber optic sensor. When a fiber optic sensor is employed, it can particularly include a fiber Bragg grating.

Hazard mitigation for railway track intrusions at train station platforms

An apparatus for use in rotational measurement. A rotational assembly is provided that is rotationally movable about a rotational axis. At least two interferometers are provided that are each able to receive a respective light beam, separate it into both reference and measuring beams and direct their respective measuring beam to and receive it back from the rotational assembly. The said rotational assembly includes a plurality of cube corners mounted so that at least one is able to receive from and reflect back to one of the interferometers its measuring beam as the rotational assembly rotates. The interferometers combine their reference and measuring beams into respective detection beams, wherein at least one such detection beam includes an interference signal that is process able to determine any rotational measurement of the rotational assembly and any work piece target attached to it.

System for rotation measurement with laser interferometry

A method establishing a reference point for a machine tool with X-, Y-, and Z-stages. A YZ-plane is established by reflecting a light beam off an X-stage reflector such that the light beam is sensed at an interference detector. The X-stage is moved while repositioning the head and reflector and maintaining sensing. An optical alignment module (OAM) is mounted optically perpendicular to the beam, with a bending mirror centered at the Z-axis. The Z-axis is established by setting the bending mirror to deflect the beam to the Z-axis, reflecting it off of a Z-stage reflector so it is sensed, and moving the Z-stage while repositioning the OAM relative to the X- and Y-axes to maintain sensing. An XY-plane is established by bending mirror deflecting the beam to the Y-axis, reflecting it off of a Y-stage reflector so it is sensed, and moving the Y-stage while repositioning the Y-reflector relative to the X- and Z-axes to maintain sensing.

Optical alignment method and apparatus

A system for tuning the wavelength of a beam from a tunable laser. A tunable etalon assembly includes a Fabry-Perot etalon with paired reflectors to filter the laser beam. The tunable etalon also includes a thermal unit to thermally adjust the separation of the paired responsive to an etalon tuning signal. A photodetector receives the laser beam after filtering the etalon and generates a detected signal based on intensity. A controller generates the etalon tuning signal, and receives the detected signal and generates a laser tuning signal based on it. Optionally, additional Fabry-Perot etalons, photodetectors, and one or more beamsplitters permit extending wavelength range and determining relative wavelength difference with a beam from a second laser.

Tunable wavelength locker, tunable wavelength spectrum monitor, and relative wavelength measurement system

An a thermal fiber Bragg grating assembly. A platform provides two attachment locations and has a first coefficient of thermal expansion. A stick provides two ends and has a second coefficient of thermal expansion. A fiber Bragg grating provides two ends and has effective third coefficient of thermal expansion. One stick end is fixed to one grating end, the other stick end is fixed to one attachment location, and the other grating end is fixed to the other attachment location. The stick has a same cross-section area along its length that is equal to or less than the cross-section area of the grating. And the coefficients and lengths between respective locations and ends are such that the assembly exhibits an effective overall coefficient of thermal expansion approaching zero.

Athermal fiber Bragg grating

A data distribution system () including an information card () and a reader (). The information card () includes visible indicia () on its front and stripe zones () and a ring zone () on its back. The zones () are suitable for magnetically recording data, and optional characteristics for such data. The reader () may be a linear reader (), a rotary reader (), or a card-stationary reader () and may optionally act automatically in response to reading one or more of the optional data characteristics. If the reader () is a rotary reader () the information card () may particularly be loaded into a cartridge () which is loaded into the rotary reader ().

A structure analysis and defect detection system in which a laser light source provides light via optical fiber to fiber Bragg gratings that change resonant frequency as stresses change in the structure. Light at the resonant frequencies of the fiber Bragg gratings is reflected and light of other frequencies is passed. The respective reflected light is directed through a Fabry-Perot interference filter or a fiber interferometer and detected by a photodetector. If the Fabry-Perot interference filter is used, the intensity of the reflected light indicates current stress at a fiber Bragg grating. If the fiber interferometer is used, a beat frequency due to heterodyne interference in the light indicates current stress at the respective fiber Bragg grating. Comparison data for the respective characteristic in the detected light over time permits stress analysis, and comparison of such data with pre-determined limit values permits defect or failure detection.

Structure analysis and defect detection system

A metering module, or a system employing such, for monitoring fluid flow with a laser light source, a light detector and a processor, wherein the fluid may be a gas or liquid. A valve section and a grating section including a fiber Bragg grating (FBG) are provided. The valve section applies strain on the FBG that is representative of the flow of the fluid. An optical fiber couples a probing laser signal to the FBG and the FBG reflects a portion back as a return laser signal that the optical fiber couples to the light detector for detection and processing.

Fiber optic flow meter

Multi-dimensional optical gratings () of a background material () having a first refractive index and cells () of at least one different refractive index. The cells () may occupy two-dimensional or three-dimensional grids, defining the optical gratings as planar gratings () or cubical gratings (), and thus providing two or three sets of surface-to-surface separations, or thicknesses, and cell-to-cell separations. The respective sets of surface-to-surface separations and cell-to-cell separations used may particularly be selected according to Bragg's law to selectively scatter respective light wavelengths.

Multidimensional optical gratings

A light wavelength meter () able to accept light into a light diverter () and impart to it a transverse displacement characteristic which can be detected in a light detection unit () connected to a processor (). Optionally, a light diverger () may be provided to enhance angular resolution. The light diverter () and the light diverger () may either transmit or reflect the light. The light diverter () may particularly include a diffraction grating (), Fabry-Perot interferometer (), multiple slit plate (), or an acousto-optical unit ().

Light wavelength meter

A light wavelength meter ( ) able to accept light into a light diverter ( ) and impart to it a transverse displacement characteristic which can be detected in a light detection unit ( ) connected to a processor ( ). Optionally, a light diverger ( ) may be provided to enhance angular resolution. The light diverter ( ) and the light diverger ( ) may either transmit or reflect the light. The light diverter ( ) may include a diffraction grating ( ), Fabry-Perot interferometer ( ), multiple slit plate ( ), or an acousto-optical unit ( ). The processor ( ) may employ wavelength data look-up tables, including addressed based on light intensity and the first defivative of light intensity.

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Saratoga, CA, United States of America

John C Tsai