Lockheed Martin Corporation

Aculight Corporation

Jason D Henrie

Matthias P Savage-Leuchs

Eric C Honea

Lawrence A Borschowa

Anping Liu

John D Minelly

Eric C Eisenberg

Barton James Jenson

Sean M Courtney

Christian D Dilley

Khushvinder S Brar

Apparatus and method for suppressing modal instabilities (MI) in fiber-amplifier systems. In some embodiments, thermal effects drive the MI process, and in some such embodiments, the present invention provides a plurality of options for mitigating these thermal effects. In some embodiments, the present invention provides a hybrid fiber with a smaller core in the initial length where the thermal loads are highest, followed by a larger-core fiber. In some embodiments the length of the smaller-core section is chosen to keep the core heat-per-unit-length of the second section below a critical value for the onset of MI. In some embodiments, the hybrid fiber of the present invention avoids modal instabilities while yielding almost the same performance as compared to conventional fibers with regard to minimizing fiber nonlinearities such as Stimulated Brillouin Scattering (SBS). In some embodiments, the hybrid fiber outputs a signal beam with at least 1 kW of power.

Fiber amplifier system for suppression of modal instabilities and method

Apparatus and method for generating controlled-linewidth laser-seed-signals for high-powered fiber-laser amplifier systems. In some embodiments, the natural chirp (frequency change of laser light over a short start-up time) of a DBR laser diode when driven by pulsed current is used to broaden the linewidth of the laser output, while adjusting the peak current and/or the pulse duration to obtain the desired linewidth.

Method and apparatus to suppress gain-switched spikes in fiber laser amplifier systems

Apparatus and method to suppress gain-switched spikes in fiber laser amplifier systems

Apparatus and method for distributed absorption of pump light over a length of delivery fiber that is, for example in some embodiments, fusion spliced to an end of a multiply clad gain fiber that has significant unused pump light at the end of the gain fiber. In some embodiments, this includes coupling a fiber amplifier to a passive-core delivery fiber that includes a distributed pump dump. In some embodiments, at an output end of the amplifying fiber there is still a significant amount of pump power. If all this pump power is dumped in one small place (e.g., at a splice between the amplifying fiber and a passive delivery fiber) a hot spot will result, leading to unreliable devices that fail (have catastrophic changes in operating performance). The present invention provides a distributed pump dump built into a delivery fiber that is passive to the signal in its core.

Method and apparatus for optical delivery fiber having cladding with absorbing regions

Apparatus and method for generating controlled-linewidth laser-seed-signals for high-powered fiber-laser amplifier systems

A method and apparatus is described that use an index-of-refraction profile having a significant central dip in refractive index (or another tailored index profile) within the core of a gain fiber or a gain waveguide on a substrate. The benefits of this central dip (more power with a given mode structure) are apparent when an input beam is akin to that of a Gaussian mode. In some embodiments, the invention provides a fiber or a substrate waveguide having an index profile with a central dip, but wherein the device has no doping. Some embodiments use a central dip surrounded by a higher-index ring in the index of refraction of the core of the fiber, while other embodiments use a trench between an intermediate-index central core portion and the ring, or use a plurality of rings and/or trenches. Some embodiments use an absorber in at least one core ring.

Apparatus and method for a waveguide with an index profile manifesting a central dip for better energy extraction

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Snohomish, WA, United States of America

Jason D Henrie