Hrl Laboratories, LLC

Hughes Aircraft Company

Hughes Electronics Corporation

Sdl Inc.

Ronald Regis Stephens

Thomas R O'Meara

Jar Jar Lee

Gregory L Tangonan

Richard C Lind

David F Welch

David M Pepper

Robert J Lang

David Alan Rockwell

Hans W Bruesselbach

Juan F Lam

Hossein H Izadpanah

Richard L Abrams

Marvin B Klein

Jack L Feinberg

Stuart MacCormack

Monica L Minden

Harry T Wang

Concetto R Giuliano

Richard R Craig

Huan W Yen

Methods and apparatus for constructing phased array antenna beamforming networks are provided, that allow to scan multiple beams and select appropriate sets of delay lines simultaneously. The beamforming networks disclosed herein generate less losses than conventional ones and in some cases, do not require active switching, making them completely passive. Three main methods are comprised in the invention: (1) laser wavelength hierarchies, (2) arrangements of Wavelengths Division Multiplexing (WDM) components, (3) re-use of laser wavelengths. Multiple laser wavelengths are arranged in groups and subgroups (wavelength hierarchies) in the wavelength domain. By switching between these wavelength groupings, the arrangements of WDM components disclosed herein enable the beamforming network to direct the beam signals to the proper time delay lines, and to differentiate multiple beams. The method of laser wavelength re-use permits to significantly reduce the number of wavelengths utilized, and thus to limit them to the standard wavelengths specified by the ITU.

Wavelength division multiplexing methods and apparatus for constructing photonic beamforming networks

A communication method comprises dividing each of a plurality of optical carrier signals into a plurality of intermediate signals wherein each optical carrier signal carrying all of a plurality of wavelength division multiplexed initial data signals and each intermediate signal carrying all of the multiplexed initial data signals over a predetermined wavelength range, separating each intermediate signal into the respective data signals contained therein, and combining corresponding data signals separated from the intermediate signals into their respective initial data signals.

Method and apparatus for passive optical extraction of signals

A method and apparatus for phased array antenna beamforming. An incoming electrical wavefront is received by an antenna. Laser light is amplitude modulated to provide a synthesized optical wavefront beam. The synthesized optical wavefront is mixed with the incoming electrical wavefront by optical modulation to provide a resultant optical waveform tilted to a coarse scan angle. The resultant optical waveform is transmitted to a predetermined delay line to provide an electrical output from the predetermined delay line corresponding to a main lobe of the resultant optical waveform.

Phased array antenna beamformer

An ultra-wideband beamformer is provided by using conventional phase shifting techniques to impress data and antenna scan information onto a narrow band signal. A non-linear element then converts the narrow sine wave into ultra-wideband pulses. Phase shift key modulation impresses data information onto the sine wave in the form of a phase shift. The data-bearing sine wave is split into multiple transmission lines where each provides an additional antenna scanning phase shift. The non-linear element converts each phase of the sine wave into short pulses which are sent to radiating elements for transmission. In the far-field of the beam, the scan delays between the radiating elements are canceled out, such that the fields from each radiating element are summed and the pulse position modulated data recovered.

Ultra-wideband pulse coincidence beamformer

Antenna structures are provided which facilitate the simultaneous radiation of multiple antenna beams. The structures include photonic manifolds that define equal-length optical paths and other optical paths whose lengths progressively change by a selected length .DELTA.L. The manifolds conduct signal pairs to radiative modules. Each signal pair includes a frequency-swept scanning signal s.sub.s and a reference signal s.sub.r whose frequency is a selected one of the sum and the difference of the frequencies of the scanning signal s.sub.s and a respective operating signal s.sub.o. Subsequently, the scanning signals are mixed with the reference signals and filtered to recover phase-shifted versions of each respective operating signal s.sub.o. The phase-shifted versions are radiated to form multiple radiated beams wherein each beam is scanned by changing the frequency of its respective scanning signal s.sub.s. The frequency of the scanning signals is selected to avoid generation of spurious radiated signals. This selection includes choosing the scanning signals so that each has a different integer number of 2.pi. phase shifts over the path length .DELTA.L. Methods of the invention permit the use of a common mixer and a common filter at each radiative module for processing all signal pairs.

Multibeam phased array antennas and methods

Wideband phased array antennas are provided that eliminate the need for phase shifters in the region of the array face. In addition, they generate less beam squint than conventional antennas. In one embodiment, they include an electronic signal generator, reference and scanning manifolds and an array of n radiative modules. The signal generator generates a variable-frequency scanning signal s.sub.s and a reference signal s.sub.r wherein the frequency of the reference signal s.sub.r is substantially a selected one of the sum and the difference of the frequencies of the scanning signal s.sub.s and an operating signal s.sub.o. The reference manifold receives and divides the reference signal s.sub.r into n reference signal samples which are progressively time delayed by a selectable one of m reference differential time delays .DELTA.t.sub.r. The scanning manifold receives and divides the scanning signal s.sub.o into n scanning signal samples which are progressively time delayed by a scanning differential time delay .DELTA.t.sub.s. Each of the radiative modules includes a mixing device, an electromagnetic radiator and a filter. The mixing device receives and mixes a respective one of the reference signal samples and a respective one of the scanning signal samples. The filter couples the mixing device to the radiator and is configured to pass the operating signal s.sub.o. Accordingly, an antenna beam is radiated from the array at m selectable scan angles with each of the scan angles varying in response to the frequency of the scanning signal s.sub.s. Multiband and two-dimensional embodiments are shown and described. The wideband characteristics of these antennas are especially suited for radar, electronic warfare and high data-rate communication applications.

Wideband phased array antennas and methods

Mixing and modulating methods are described for nonlinear optical amplifiers (30) which can generate intermodulation products of radio-frequency signals in an optical carrier signal (26) without the penalty of an optical conversion loss and without the need for radio-frequency mixers, electro-optic modulators and expensive polarization-maintaining optical fibers. The radio-frequency signals can be applied to either a bias port (36) or an optical input port (32) of the optical amplifier and are used to upconvert and downconvert signals in phased-array antenna and remote antenna embodiments of the invention.

Mixing and modulating methods and structures using nonlinear optical

An optical amplification system directs a diffraction-limited signal beam through a series of approximately 90.degree. crossings with a number of non-diffraction-limited pump beams in a photorefractive medium. All of the beams are s-polarized, resulting in an energy transfer from the pumps to the signal beam while leaving the signal beam diffraction-limited. The photorefractive medium is preferably a series of BaTiO.sub.3 :Rh crystals that receive the pump and signal beams through orthogonal faces, with their C-axes at approximately 45.degree. to both beams. A binary tree optical distribution network is used to minimize waveguide splits in forming a large number of pump beams. The outputs of several amplification modules are combined into a single output beam using adaptive optics, with the outputs from the different modules phase matched to each other by diverting two minor portions of the combined beam, partially overlapping the diverted beams and adjusting the amplification module phases to cancel phase differentials between the overlapped portions. Similarly, sets of combined and phase-matched beams can be combined with each other (again using adaptive optics) to generate still higher powers using a super module approach.

Hybrid laser power combining and beam cleanup system using nonlinear and

A spectral narrowing of the output bandwidth from a laser array is obtained by feeding back to the array a portion of its emitted light, while outputting the remainder of the light emitted from the array. An optical system to accomplish this preferably includes a pair of lenses, together with a diffraction grating that can be positioned either in-line with the laser array and lenses, or in a side-arm along with one of the lenses. The lenses can be set up so that light from each laser element is fed back either to itself, or to a symmetrically located element on the opposite side of the system axis. For a multi-lobe output from the laser array, one of the lobes is used for feedback and the others as outputs, resulting in a narrowing of the output angular divergence as well as of the output bandwidth.

Narrow bandwidth laser array system

A rectangular light pipe (38) and associated optical elements (36), (40) are used to produce an overlapped combination of an array of aberrated laser beams (32), (34) inside a phase conjugate mirror (42). The beam array (32), (34) is focussed onto the entrance face (38a) of the light pipe (38) in such a way that each beam (32), (34) spreads by diffraction and internal reflections to fill the exit face (38b) of the light pipe (38). An image of the exit face (38b), which is completely filled by the overlapped beams (32), (34), is focussed into the phase conjugate mirror (42) such as to produce an overlap spot (46) size which is independent of beam aberation level. The apparatus preserves the linear polarization of the input beams (32), (34), has low optical loss, and may be incorporated into a 2 pass (50), (74) or 4 pass (80) phase conjugate master-oscillator power amplifier.

Growing community of inventors

Westlake Village, CA, United States of America

Ronald Regis Stephens