Abstract: An electro-optic device with a doped semiconductor base and a plurality of pixels on the semiconductor base. Pixels include oppositely doped semiconductor layer and a top electrode formed on the oppositely doped semiconductor layer. The top electrode has a grid pattern with at least one busbar and a plurality of fingers extending from the busbar, and spacing between the fingers decreases with distance from the bondpad along the busbar. Each pixel can also include a multiple quantum well formed on the semiconductor base. The top electrode shape produces an approximately uniform lateral resistance in the pixel. An embodiment is a large area modulator for modulating retro-reflector systems, which typically use large area surface-normal modulators with large lateral current flow. Uniform resistance to each part of the modulator decreases location dependence of frequency response. A chirped grid electrode balances semiconductor sheet resistance and metal line resistance components of the series resistance.

Abstract: A microbend accelerometer comprising a housing having a housing base and a housing top, where housing base has corrugations that protrude from the surface of the housing and an internal mass assembly located between the housing top and the side of the housing base. The internal mass assembly features corrugations that are similar to the housing base corrugations. The microbend accelerometer also features a sensing fiber featuring light propagating therethrough, said sensing fiber disposed between said internal mass and said housing base, said sensing fiber being coupled on each end to at least one lead fiber. Upon an acceleration event along a predetermined axis, inertia causes the internal mass assembly to apply a force on the sensing fiber causing the sensing fiber to distort. This resulting distortion of the sensing fiber causes the intensity of the light propagating through the sensing fiber to modulate in proportion to the magnitude of said acceleration event.

Abstract: A system for the accurate determination of the position of an underwater vehicle comprising a system observer subsystem having a state velocity update module, a terrain matching module, means for generating a prediction of the terrain matching module's performance and a constrained extended Kalman filter subsystem. The constrained extended Kalman filter subsystem includes a steady state extended Kalman filter, a non-linear constraint module, and a state predictor.

Abstract: The apparatus for cooling a high power electrical transformer and electrical motors uses thermally conductive material interleaved between the turn layers of a high power transformer and iron core laminates to provide a low resistant thermal path to ambient. The strips direct excess heat from within the interior to protrusions outside of the windings (and core) where forced air or thermally conductive potting compound extracts the heat. This technique provides for a significant reduction of weight and volume along with a substantial increase in the power density while operating at a modest elevated temperature above ambient.

Abstract: An apparatus and method to increase the output power from LiNbO3 MZM style optical intensity modulating without exceeding the optical power damage threshold imposed by LiNbO3 is described. The optical path from a laser source is divided into two paths by a polarization maintaining (PM) coupler. The two paths form a Mach Zender Modulator (MZM) with a LiNbO3 phase modulator in one path and a fiber looped PZT in the other. The LiNbO3 phase modulator imprints an RF signal onto one path of the MZM cavity, while the fiber wrapped PZT is used to control the path length difference between the two optical paths. The two optical paths are recombined in a second PM coupler.

Abstract: Featured is a high power, broadband superfluorescent source with very low relative intensity noise (RIN) including a seed source, a modulator operably coupled to the seed source and a polarization maintaining (PM) amplifier operably coupled to the modulator. The output of the seed source is processed in the modulator so the modulator outputs a polarized optical output to the PM amplifier. The PM amplifier amplifies the modulated, polarized optical output so as to provide an amplified polarized optical output therefrom. Also featured is a feedback circuit operably coupled to the PM amplifier to control the transmission of the modulator so as to minimize the amplitude fluctuations in the output signal. Such a source is advantageous in high precision fiber optical rotation sensors and multiplexed strain sensing arrays.

Abstract: An acoustic actuator comprises a radially poled piezoelectric or electrostrictive drive element which is electroded on its inner and outer faces, and an acoustic diaphragm coupled to the upper surface of the piezoelectric drive element. As a voltage is applied to the electrodes, the piezoelectric drive element expands and contracts in the radial direction and the acoustic diaphragm displaces upward or downward, generating a sound wave. In an alternative embodiment, the piezoelectric or electrostrictive drive element is comprised of several subelements laid end to end and radially poled. In another embodiment, the piezoelectric or electrostrictive drive element is comprised of several subelements laid end to end which are thickness-poled reduced and internally biased oxide wafers of piezoelectric material.

Abstract: A circuit for selectably generating a plurality of preselected digital output signals which are precise and accurate, and among which the circuit can switch rapidly. In one embodiment, the outputs are connected to analog circuit signals, and drive a optical laser such that choice of the particular outputs of the circuit permits controllable switching of the laser output wavelength.

Abstract: A novel method and apparatus for signal processing are described which discriminate between signals and noise based on the magnitude of the phase fluctuations. In an embodiment of the invention, the governing equations of the process adaptively change in response to the phase and amplitude characteristics of the signals being received for processing. In an embodiment of the invention, an automatic detection method and apparatus is described which has the capability to alert an operator of the presence of signals having phase fluctuation characteristics which match a set of preset conditions (e.g. small fluctuations, medium fluctuations, or large fluctuations).

Abstract: Channel doping and gate lithography are simulatneously performed by focusing an ion beam into the wafer through a positive or negative photoresist that is sensitive to the ion beam. Additional fabrication is then performed to provide a gate that is self-aligned with the doped channel.

Abstract: A system is disclosed for measuring strain using a technique of detecting the optical path difference in a sensing interferometer using an interrogating interferometer including a chirped fiber Bragg grating in which the optical path difference in the sensing interferometer is changed with the strain in the sensing arm, whereas the optical path difference of the interrogating interferometer is changed only by changing the center wavelength of addressing light, making use of the wavelength-dependency on the penetration depth inside the chirped fiber Bragg grating interferometer. Consequently, strain in the sensing interferometer can be assessed by determining the wavelength in which a coherence matched condition between the sensing and interrogation interferometers is attained.

Abstract: A fiber optic sensor array has multiple segments, each capable of detecting a physical condition such as an acoustic wave. The segments are separated by weak reflectors such as fiber optic Bragg gratings. Light from a light source is input into the input end of the array. Light reflected by each of the reflectors has a phase shift representing the effects of the physical condition on all of the segments from the input end to that reflector. To address a specific reflector, the return light is demultiplexed. This demultiplexing is done by modulating the light input into the input end of the array with a pseudo-random bit sequence and correlating the output with a time-shifted version of the pseudo-random bit sequence to isolate the part of the output caused by that reflector. To address a specific segment, the phase shifts from two adjacent reflectors are determined. The return light can be strengthened by mixing it with a portion of the light picked off from the light source.

Abstract: A dual-energy x-ray system is provided which is useful in densitometry and other applications. A dual energy x-ray source, formed field emission x-ray tube driven by a Marx generator, produces a single x-ray pulse of a very short duration (e.g., 10 to 200 nanoseconds). The pulse provides x-ray energy of a first, high value early in the pulse and x-ray energy of a second, lower value later in the pulse so as to provide a dual energy level x-ray distribution comprising hard and soft x-rays. A detector system having dual x-ray energy discrimination properties, formed by soft and hard x-ray detectors and an inter-detector, receives the x-ray pulse and discriminates between the dual x-ray energy levels of the pulse.

Abstract: A reflective Bragg grating in the interior of an infrared transmitting glass fiber, and a method for fabricating such reflective Bragg grating in the interior of the infrared transmitting glass fiber is disclosed.

Abstract: This invention is a one-dimensional optic flow sensor that operates in a small region of the two-dimensional visual field. The heart of the sensor is an linear array of photoreceptors that generates a one-dimensional image representation of the visual field region of interest. The linear photoreceptor array has an orientation in the two-dimensional image space. Information in the two-dimensional image space parallel to the photoreceptor array's orientation is preserved while information in other directions is discarded. The result is that a one-dimensional optic flow algorithm using the photoreceptor array output produces a measurement of the optic flow vector onto the sensor orientation vector. In a preferred embodiment, the photoreceptor array circuitry is implemented on a focal plane chip on which an image is focused by a lens. The focal plane chip is placed slightly off the lens's focal point to blur the image.

Abstract: A new technique of optical bandgap thermometry allows one to accurately measure the temperature of semiconductor samples by using the temperature dependent reflective properties of the samples. The disclosed technique uses specular reflection at an oblique angle of incidence. Light from a light source such as quartz halogen lamp is chopped and focused by a lens. The light then is focused onto the sample at an oblique angle of incidence. The light is specularly reflected by the sample and is focused by a lens into a spectrometer. The spectrometer is used to determine the spectrum of the light reflected from the sample. The reflectance varies with temperature and the temperature of the sample is calculated as a function of the reflectance spectrum.

Abstract: A new fiber optic based beamforming architecture for a time steered phased rray antenna based on chirped fiber gratings. All of the gratings are identical in length and period chirp so that they all have the same dispersion, thus at a given optical wavelength they have the same time delay. In a preferred embodiment an optical signal is modulated with an RF signal. The RF modulated optical is split and a portion propagates through a length of fiber to a photodetector feeding an antenna array. The second portion of the optical signal is routed through a circulator, which feeds the optical signal to a chirped fiber grating. The grating reflects and delays the optical signal back to the circulator which routes the reflected optical signal to a second coupler. The amount of delay incurred is determined by the grating dispersion and the wavelength of the optical source.

Abstract: A channelized active bandpass filter having only two branches which provide respective frequency-selective feed-forward signal paths. The two signal aths have overlapping frequency response bands such that the combination of the two paths provides a composite filter with a bandpass response. The two branches may be provided with bandpass transfer characteristics of different orders and shapes, such as a second-order response and a fourth-order response. Two-way signal splitting and combining to define the two channels may be performed with in-phase splitters and combiners, for example, or diplexer circuits, each composed of two bandpass filters with different characteristics but overlapping frequency responses and preferably approximately equal center frequencies. Combinations of the two splitting and combining arrangements are also usable.