Northrop Grumman Systems Corporation

Other

Trw Limited

Northrop Grumman Space & Mission Systems Corporation

Mark Ernest Weber

Gregory Douglas Goodno

Eric C Cheung

Stanley Benjamin Weiss, Iv

Robert R Rice

Michael G Wickham

Stephen P Palese

Hagop Injeyan

Stephen John Brosnan

Chun-Ching Shih

Randall J St Pierre

Mark LeRoy Simonds

Eric Chiu-Tat Cheng

Arthur L Martin

Stanley Benjamin Iv Weiss

An electro-optical modulator (EOM) array that simultaneously modulates a plurality of optical beams. The EOM array has particular application for use in a seed beam source for an SBC fiber laser amplifier system, where the seed beam source includes a plurality of master oscillators each providing an optical seed beam at a different wavelength on a fiber. The EOM array has a common substrate, a plurality of parallel waveguides and an electrode structure, where each waveguide is coupled to one of the fibers to receive one of the seed beams. An RF source provides an RF drive signal to the electrode structure that modulates the seed beams. The fiber laser amplifier system amplifies each of the seed beams from the EOM array, and includes an SBC grating that spatially combines the amplified beams at the different wavelengths so that they are directed in the same direction as an output beam.

Common drive electro-optic phase modulator array

A tensioning device and method for post-tensioning a concrete member having at least one crack is provided. The tensioning device may include an elongated body, a stitch catch arm and an anchor. The catch arm may be perpendicularly joined to one end of the elongated body, wherein the catch arm is inserted into a hole in the concrete member. The elongated body may form an anchor recess therein, wherein an anchor interface surface is defined by the anchor recess. The anchor interface may form an anchor aperture for receiving the anchor. The thickness of the anchor interface may uniformly decrease as the anchor interface extends toward the catch arm end of the anchor recess so that when ratcheting the anchor into the concrete member and onto the anchor interface a portion of the applied compressive force and/or torque may be transformed into an axial force along the elongated body so as to provide post-tensioning through the tensioning device and across the at least one crack.

Method and apparatus for adjustable post-tensioning of concrete

A multichannel optical system including a mixing device responsive to a sample beam and a reference beam that provides an in-phase signal including the mixed sample beam and reference beam having a relative phase of 0&#xb0; and a quadrature phase signal including the mixed sample beam and reference beam having a relative phase of 90&#xb0;. The system also includes a photodetector responsive to the quadrature phase signal that converts the quadrature phase signal to a quadrature phase electrical signal. A polarization demultiplexer circuit receives the quadrature phase electrical signal and measures the amplitude of a unique time-dependent phase dither profile having a zero time-averaged mean and a zero time-averaged correlation to the other phase dither profiles and provides a polarization amplitude signal. A polarization controller receives the polarization amplitude signal and controls the reference beam to maximize the polarization amplitude signal.

Multichannel polarization stabilization employing synchronous phase-locking methods

A multichannel polarization stabilizer including a mixing device responsive to a sample beam and a reference beam that provides an in-phase signal including the mixed sample beam and reference beam having a relative phase of 0&#xb0; and a quadrature phase signal including the mixed sample beam and reference beam having a relative phase of 90&#xb0;. The stabilizer also includes a photodetector responsive to the quadrature phase signal that converts the quadrature phase signal to a quadrature phase electrical signal. A polarization demultiplexer circuit receives the quadrature phase electrical signal and measures the amplitude of a frequency tone in the sample beam and provides a polarization amplitude signal. A polarization controller receives the polarization amplitude signal and controls the reference beam to maximize the polarization amplitude signal.

Multichannel polarization stabilizer

A pulsed fiber array laser system that has actively stabilized coherent beam combination (CBC) is disclosed. The active stabilization is accomplished using both piston phase control and intra-pulse phase control, allowing a much greater increase in pulse energy. Further stabilization using intra-pulse amplitude control is also disclosed. A chirp profile can be written on the output pulse to enable specific applications. An amplitude profile of the amplifier array may optionally be tailored to match to a reference electrical pulse. Using the current invention, a much smaller number of amplifier chains will be needed to achieve certain pulse energy, resulting in a system with lower complexity, lower cost, smaller size, less weight, and higher reliability.

Coherently phase combined, high contrast, pulsed optical fiber amplifier array

An electronic sensor module for us in an interactive system, such as an interactive sports training device, for accurately detecting a projectile brought within close proximity of a target. The sensor module includes a plurality of light sources arranged in a housing such that the light sources are visible through a surface of the housing when activated. A plurality of sensors are also arranged in the housing for detecting the presence of a projectile. In one aspect, the sensors are arranged in a polar array about a center of housing with spaces between adjacent sensors, and with a light source positioned in each space between adjacent sensors.

Sensor module

A pulsed coherent fiber array laser system that includes a beam generating sub-system that provides a signal pulse beam having pulses of the desired duration that is split into several fiber channels. Optical leakage between the pulses in each split beam is measured and locked to a reference beam by a phase sensing circuit and phase adjusters so that the phase of each fiber pulsed beam is aligned with the phase of the reference beam. A pulse clipper or filter is employed to remove the pulses in the fiber beams so that they do not saturate the phase sensing circuit. The beam generating sub-system can employ any suitable combination of devices to generate the signal beam and the reference beam, including continuous wave master oscillators, amplitude modulators, frequency shifters, injection seed oscillators, Q-switched lasers, reference oscillators, frequency lockers, wavelength division multiplexers, time gated switches, etc.

Pulsed coherent fiber array and method

A hybrid optical/electronic wavefront sensor includes an electro-acoustical device used to upshift an optical reference signal. An optical test signal and the frequency upshifted optical reference signal are optically heterodyned to create a signal having a frequency equivalent to the beat frequency of the two signals, for example, the RF driving frequency of the Bragg cell. The optically heterodyned signal is then converted by way of a detector to an electronic signal having the same phase as the optical test signal. The output of the detector is a sinusoidal signal having the same phase as the phase of the optical test signal. This signal is filtered by way of an AC filter and mixed with a second clock signal, for example, a clock signal that is offset in frequency from the electro-acoustical drive signal by a frequency, for example, between 100 kHz and 1 MHz. These two signals are mixed by way of a mixer. The low frequency product of the mixer is passed by way of a filter and converted to a square wave by way of a comparator. The output of the comparator is applied to a simple pulse counter and used to disable the pulse counter. The pulse counter counts the clock pulses while it is enabled and is linearly related to the difference in phase between the optical test signal and the frequency upshifted signal.

Wavefront sensor using hybrid optical/electronic heterodyne techniques

A system and method for monitoring the mode of an input beam to a phase conjugated master oscillator power amplifier (PC MOPA). In order to prevent catastrophic optical damage to the MOPA components, the method and system shuts down the master oscillator when a multi-mode input beam is detected.

Phase conjugated master oscillator-power amplifier breakdown control

A digital pulse generator having a high-speed clock (22) and two clock pulse counters (10 and 12), one (10) to time the start of each pulse and one (12) to time the pulsewidth, based on clock counts supplied from a microcontroller (14) to which a user inputs desired pulse parameters. The combination of the high-speed clock (22) and the clock pulse counters (10 and 12) produces precise and reliable output pulses for a variety of applications, and at a relatively low cost. Operation may be selected to be in internal mode, in which successive pulses are produced at a desired period, or an external mode, in which a pulse is generated after a selected time delay. A trigger signal input circuit (48, 32) and a trigger signal output circuit (42), both with adjustable impedances, facilitate interconnection of multiple digital pulse generators as needed for a given application.

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Hawthorne, CA, United States of America

Mark Ernest Weber