Northrop Grumman Systems Corporation

Trw Limited

Eric C Cheung

Gregory Douglas Goodno

Stephen P Palese

Hagop Injeyan

James G Ho

William H Long

Peter Anthony Thielen

Mark Ernest Weber

Joshua E Rothenberg

Michael G Wickham

Hiroshi Komine

Timothy S McComb

Chun-Ching Shih

A WDM seed beam source for a fiber laser amplifier system that includes a number of master oscillators that generate seed beams at different wavelengths and a spectral multiplexer that multiplexes all of the seed beams onto a single fiber. An EOM modulates the combined seed beams on the single fiber and a spectral demultiplexer then separates the modulated seed beams into their constituent wavelengths on separate fibers before the seed beams are amplified and spectrally combined. The fiber laser amplifier system includes a separate fiber amplifier that amplifies the separated seed beams, an emitter array that directs the amplified beams into free space, beam collimating optics that focuses the uncombined beams, and an SBC grating responsive to the collimated uncombined beams that spatially combines the collimated uncombined beams.

Wavelength division multiplexing (WDM) beam source

Combined laser architecture using wavelength multiplexed seed source

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

An optical system, such as a fiber laser amplifier, including a plurality of optical sources, such as fiber amplifiers, each generating a beam. In one embodiment, the system includes first and second diffraction gratings that correct the angle of the propagation direction of the beams to remove angular dispersion caused by a diffractive optical element (DOE). In another embodiment, the system includes a single diffraction grating, where the optical beams pass through the grating twice to also remove the angular dispersion caused by the DOE.

Dispersion compensated diffractive optical element beam combiner

A system includes N master oscillators to generate N master oscillator driving signals. The system includes N splitters to split each of the N master oscillator signals into M coherent signals with M being a positive integer greater than one. A modulator and fiber amplifier stage adjusts the relative phases of the M coherent signals and generates M&#xd7;N amplified signals. The M&#xd7;N amplified signals are aggregated into M clusters of N fibers. The system includes M spectral beam combination (SBC) modules to combine each of the M clusters. Each SBC module combines the M&#xd7;N amplified signals at N wavelengths and generates M tiled output beams. Each SBC module employs a single dimensional (1D) fiber optic array to transmit one cluster of N amplified signals from the M signal clusters and generates one tiled output beam of the M tiled output beams.

Hybrid spectral and coherent beam combiner utilizing 1D fiber arrays

A system for providing a sliced optical pulse is disclosed. The system can comprise a master oscillator (MO) configured to generate an optical pulse at a first spectral bandwidth. The system can also comprise a semiconductor optical amplifier (SOA) configured to slice the optical pulse to generate a sliced optical pulse that has a second spectral bandwidth. The second spectral bandwidth can be smaller than the first spectral bandwidth.

Systems and methods for generating an optical pulse

A method of spectral beam combining comprising the steps of projecting a plurality of laser beamlets of different wavelengths onto a first spectrally dispersive element, spatially chirping the plurality of beamlets via the first spectrally dispersive element, rearranging the spatially chirped beamlets with a beam redirecting element, and combining the beamlets into a single output beam via a second spectrally dispersive element.

Spectral beam combining and wavelength multiplexing with an optical redirecting element

A nested loop system for combining coherent laser beams, The system includes multiple laser amplifiers each configured for emitting one of the laser beams, an output beam splitter configured for sampling each laser beam and for coupling each sampled laser beam to an inner feedback loop module, an output beam sampler configured for splitting the combined beam into a primary and a sampled output beam and for coupling the sampled output beam to the inner feedback loop module, multiple inner loop phase modulators each paired with one of the laser amplifiers, and the inner feedback loop module. For each laser amplifier the inner feedback loop module is configured to use the sampled output beam and the sampled laser beam associated with that laser amplifier to create a different inner loop feedback signal and to couple that inner loop feedback signal to that laser amplifier paired inner loop phase modulator.

Nested loop coherent beam combining system

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

A high-energy optical beam generator providing a desired output waveform. The generator includes a master oscillator, such as a mode-locked laser, to generate an input beam, a first dispersive element to decompose the input beam into frequency components, a set of phase and amplitude modulators to modulate the frequency components individually, a set of power amplifiers to amplify the frequency components individually, and a second dispersive element to recombine the amplified and modulated frequency components into a single output beam. Phase control electronics control the modulators to provide the desired waveform for the output beam, based on its intended application and on sensed characteristics of the input beam and the output beam.

High energy arbitrary waveform source

A high efficiency solid state Raman laser system for shifting the frequency of an input beam emitted by a laser pumping system is described. The laser pumping system suppresses relaxation oscillations in the input beam and emits a constant power, mode-locked pulse train. A solid Raman medium is disposed inside a Raman resonator cavity to shift the frequency of the input beam to produce a Raman beam. The frequency of the Raman beam is finely tuned in the resonator cavity to eliminate high order Raman shifted wavelengths. The polarization of the Raman beam is selected using a polarizing element disposed in the resonator cavity. The Raman beam frequency is shifted using a non-linear medium inside the resonator cavity. The non-linear medium is preferably a frequency doubler. The Raman laser system is particularly suitable for producing high-quality yellow light for guide star applications.

High efficiency solid state raman laser system

An intracavity doubled solid state Raman laser system for converting the frequency of a laser input beam emitted by a laser pumping system is described. A solid Raman medium is disposed within a resonator cavity to shift the frequency of the input beam to produce a Raman beam. The frequency of the Raman beam is tuned in the resonator cavity preferably using an etalon and a birefringent filter. The polarization of the Raman beam is selected using a polarizing element disposed in the resonator cavity. The Raman beam frequency is doubled using a non-linear doubling medium inside the resonator cavity. The Raman laser system is particularly suitable for producing yellow light.

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Torrance, CA, United States of America

Eric C Cheung