Abstract: A proximity sensor having a generator providing a signal of which a small portion is used as a reference signal and the remaining portion is radiated out towards a target. The radiation reflected from the target is equalized and/or normalized relative to the reference signal. The signals are compared in terms of relative phase relationship. This relationship implies the distance of the target from an antenna. An example target may be a rail wheel. A certain part of the wheel is measured in terms of distance from the sensor. This distance may determine wheel wear. Such wear is gauged relative to a threshold signal or reference distance. Also, speed and direction of the rail wheel can be determined from the signal reflected back to the proximity sensor.

Abstract: A method for fabricating a wafer-pair having at least one recess in one wafer and the recess formed into a chamber with the attaching of the other wafer which has a port plugged with a deposited layer on its external surface. The deposition of the layer may be performed in a very low pressure environment, thus assuring the same kind of environment in the sealed chamber. The chamber may enclose at least one device such as a thermoelectric sensor, bolometer, emitter or other kind of device. The wafer-pair typically will have numerous chambers, with devices, respectively, and may be divided into a multiplicity of chips.

Abstract: A very high temperature microbeam sensor of a resonant integrated microstructure having an electrostatic beam driver and an optical fiber pick-up for sensed light from the beam. The high temperature sensor has no components that are vulnerable to temperatures up to 600 degrees C. Associated components for detection, processing and driving are remote from the sensor environment. By using different materials in the beam assembly, such as tungsten for the beam, and sapphire for the substrate and the shell, the sensor can withstand temperatures up to 1000 degrees C. Also, optical fiber may be used for long distance connections between processing electronics and the driver in the sensing device, by locating a photo detector just outside the very or ultra high temperature sensing environment, and then using optical fiber for sending long distance signals from the processor to the driver photo detector, for eliminating electrical signal-to-noise problems.

Abstract: An acoustic rotor monitor that is an autonomous self-powered measurement instrument which can detect embedded and hidden fatigue cracks in remotely inaccessible devices such as helicopter rotor system components. A predictive maintenance-related problem for rotor craft is the detection of fatigue cracks as a continuous real-time monitoring process under dynamic rotor system loading conditions. The rotor monitor focuses on the embedding an acoustic emission-based smart sensor directly into the rotor system to measure the high frequency stress waves indicating that a structural crack has propagated as a "self-powered" measurement without reducing structural integrity.

Abstract: A gas-air mixing valve using a tube. The valve has an internal geometry shape for directing the flow of air and gas, including an air inlet, an inlet part from the inlet to a throttle, a gas inlet slot proximate the throttle, and an outlet. The inlet part has a first body part, preferably of aluminum or other metal, and a replaceable molded part normally of plastic. The first body part has an inlet surface centered about a central axis defined by a concave surface having a first circular cross section. The replaceable molden part has a composite surface defined by conical surface defined by conical surface having a linear cross section and further defined by a convex surface having a second circular cross section forming the throttle. The replaceable molden outlet part has a conical surface extending from the second circular cross section to a second convex surface at the outlet.

Abstract: A relay device build using MEMS technology and having a semiconductor wafer base with a surface depression having a first electrically conductive surface pattern. A lower diaphragm is moveably positioned above the depression for contact and has a second electrically conductive surface pattern thereon. An upper diaphragm is positioned above the lower diaphragm, with a central electrode mounted between them to selectively attract and move a diaphragm upon application of voltage. A post connects the upper and lower diaphragms to move a diaphragm when the other is moved electrostatically. The diaphragms define a sealed region enclosing the central electrode. The surface patterns may be tapered at their perimiters to provide a contact contour allowing gradually increasing contact as the diaphragm moves toward the surface. The preferred wafer is a silicon wafer, and the diaphragms are polysilicon.

Abstract: A rectification error reducer for a fiber optic gyroscope, which is an intensity servo or compensator for reducing vibration effects in the optical signals caused by modulation at vibration frequencies induced by the gyroscope operating environment. The vibration effects may be detected in signals from the photodiode output in amplitude form which is used in a control system to null out optical intensity variations at the frequencies of vibration.

Abstract: A rectification error reducer for a fiber optic gyroscope, which is an intensity servo or compensator for reducing vibration effects in the optical signals caused by modulation at vibration frequencies induced by the gyroscope operating environment. The vibration effects may be detected in signals from the photodiode output in amplitude form which is used in a control system to null out optical intensity variations at the frequencies of vibration.

Abstract: A multipath detection method for use in a GPS position determination system includes providing a code pseudorange measurement representative of a range of an antenna to a space vehicle and a carrier phase pseudorange measurement representative of the range of the antenna to the space vehicle. A code-carrier measurement difference is then generated between the code pseudorange measurement and the carrier phase pseudorange measurement. This code-carrier measurement difference is examined to determine if a multipath component is present. If, the difference indicates that multipath is likely to be present, use of such measurements in computing position solutions, such as attitude solutions, is avoided. A multipath detection system for carrying out the method is also described.

Abstract: An electrostatic actuator device including a stationary support and a buckled, moveable support mounted to enter into contact with the stationary support. At least three electrodes are employed. The first is mounted on the moveable support and a second electrode is on the stationary support. A third electrode is mounted on one of the supports such that the electrodes are positioned to form two pairs of electrodes for electrostatic attraction therebetween. The electrodes are powered by a voltage supply to provide electrostatic attraction between pairs of electrodes and move them into electrostatic contact. The buckled electrode has a shape configured to transmit a restoring force to its portion in contact with stationary support upon application of voltage to another pair of electrodes.

Abstract: A laser structure is provided with two current confining layers of a material that is subject to oxidation in the presence of an oxidizing agent. The laser structure is shaped to expose edges of the current confining layers to permit the edges to be exposed to the oxidizing agent. The current confining layers are oxidized selectively to create electrically resistive material at the oxidized portions and electrically conductive material at the unoxidized portions. The unoxidized portions of the layers are surrounded by the oxidized and electrically resistive portions in order to direct current from one electrical contact pad by passing through a preselected portion of an active region of the laser. The laser structure can be a vertical cavity surface emitting laser. The device achieves the current confining and directing function without the need to use ion bombardment or implantation to provide the current confining structure within the body of the laser.

Abstract: A vertical cavity surface emitting laser having a planar structure, having an implantation or diffusion at the top of the mirror closest to the substrate or at the bottom of the mirror farthest from the substrate, to provide current confinement with the gain region, and having an active region and another mirror formed subsequent to the implantation or diffusion. This structure has an implantation or diffusion that does not damage or detrimentally affect the gain region, and does provide dimensions of current confinement that are accurately ascertained. Alternatively, the implantation or diffusion for current confinement may be placed within the top mirror, and several layers above the active region, still with minimal damage to the gain region and having a well-ascertained current confinement dimension.

Abstract: A micromachined integrated opto-thermal sensor having a rapidly intensity varying or pulsing light source, an interference filter, shadow masking or reflective blocking of light from thermal sensors, or differential operation, a gas cavity into which the detected gas can flow into via a channel or filter, and a thermal detector elements to sense the heating of the gas caused by the absorption of light at a particular wavelength by the specific gas to be detected. Another version of the sensor is one with a dual cavity. One cavity contains the gas to be detected and the other cavity is sealed from the ambient environment and contains no gas. Signals from the detectors from the cavities are subtracted from each other resulting in the elimination of a fixed signal due to radiation impinging the detectors.

Abstract: A micromachined integrated opto-fluidic or opto-acoustic sensor having a rapidly intensity-varying or pulsing light source, an interference filter, a gas cavity, which may or may not be an optical and/or acoustic resonator tuned to a particular wavelength of light, or sound frequency, into which the detected gas can diffuse into via a filter, and a fluidic or pressure sensor to detect the heating and cooling, and the resulting expansion and contraction of the gas due to the absorption of light at the particular wavelength by the specific gas being detected. The presence of other gases is inferred from the detected gas.

Abstract: Aligned birefringent fiber segments are reliably and efficiently rotated approximately 45.degree. relative to each other until the extinction ratio measurement at the output is approximately 0 dB, then birefringent fibers are fused. To determine the extinction ratio, a Wollaston analyzer is placed at the output of the birefringent fiber. Photodetectors placed on each output of the Wollaston analyzer, substantially simultaneously measure the output intensity of each propagation axis.

Abstract: A micromachined integrated opto-fluidic or opto-acoustic sensor having a rapidly intensity-varying or pulsing light source, an interference filter, a gas cavity, which may or may not be an optical and/or acoustic resonator tuned to a particular wavelength of light, or sound frequency, into which the detected gas can diffuse into via a filter, and a fluidic or pressure sensor to detect the heating and cooling, and the resulting expansion and contraction of the gas due to the absorption of light at the particular wavelength by the specific gas being detected. The presence of other gases is inferred from the detected gas.

Abstract: A micromachined integrated opto-thermal sensor having a rapidly intensity varying or pulsing light source, an interference filter, shadow masking or reflective blocking of light from thermal sensors, or differential operation, a gas cavity into which the detected gas can flow into via a channel or filter, and thermal detector elements to sense the heating of the gas caused by the absorption of light at a particular wavelength by the specific gas to be detected. Another version of the sensor is one with a dual cavity. One cavity contains the gas to be detected and the other cavity is sealed from the ambient environment and contains no gas. Signals from the detectors from the cavities are subtracted from each other resulting in the elimination of a fixed signal due to radiation impinging the detectors.

Abstract: A gyroscope having three fiber optic loops for sensing rates of rotation in three axes orthogonal to one another. The gyroscope has one or two detectors and one source that is shared among the three fiber optic sensing loop subsystems with a special multi-coupler configuration. Also, portions of the rotation rate signal processing electronics, whether an open or closed loop configuration, are shared among the three sensing loops. The gyroscope may be a single mode optical fiber depolarized configuration or a polarization maintaining optical fiber configuration.

Abstract: A two-level IR detector imaging array of high fill-factor design. The upper microbridge detector level is spaced above and overlie the integrated circuit and bus lines on the substrate surface below.

Abstract: In a microbolometer infrared radiation sensor, a detector material (VO.sub.2) having a high thermal coefficient of resistance to increase the sensitivity of the apparatus.