Raytheon Company

Friedrich P Strohkendl

Michael Ushinsky

David Alan Rockwell

Carl W Townsend

Joseph L Pikulski

Vladimir V Shkunov

Makan Mohageg

Ray E McVey

Jeffrey P Yanevich

An apparatus includes a base having walls that define a track. The track has input and output ends and defines a coiled path that spirals inward from the input end, reaches an inflection point where a direction of curvature is reversed, and spirals outward towards the output end. The track is configured to receive and maintain a majority of an optical fiber in an at least substantially planar coiled arrangement. The apparatus also includes a first transition arm positioned at the input end and a second transition arm positioned at the output end. Each transition arm is configured to be mechanically coupled to the base and includes a groove configured to receive and maintain a portion of the optical fiber in an at least substantially straight orientation. The walls and transition arms are configured to maintain thermal contact with the optical fiber along its entire length.

Compact package for high-aspect-ratio rectangular (HARR) optical fiber or other optical fiber

Systems and methods described herein provide a thermally compensated waveguide structure having a thermal index profile configured to correct thermal aberrations caused by temperature gradients in a fast axis direction and/or correct other forms of distortions in an output beam generated by the waveguide structure. The waveguide structure includes a core region, one or more cladding, and one or more heat sinks. A geometry of these portions with respect to each other can provide a cold refractive index profile such that a cold refractive index value of a portion of the core region is less than a cold refractive index value of at least one of the one or more cladding regions. Responsive to thermal compensation, the cold refractive index profile is modified, through addition of a thermal index profile, to form a hot index profile having attributes including good overlap of the fundamental mode with the gain profile and mode clean-up through gain discrimination against higher order modes.

Fast axis thermal lens compensation for a planar amplifier structure

An apparatus includes a PWG having a core region and a cladding layer. The amplifier is configured to receive pump light. The core region is configured to amplify an input beam using energy from the pump light to generate an amplified output beam. The apparatus also includes a cooling fluid configured to cool the core region. The cooling fluid has a lower refractive index than the core region and the cladding layer in order to support guiding of the input beam and pump light within the amplifier. The amplifier also includes first and second endcaps attached to opposite faces of the core region and cladding layer. The core region, cladding layer, and endcaps collectively form a monolithic fused structure. Each endcap has a major outer surface that is larger in area than a combined area of the faces of the core region and cladding layer to which the endcap is attached.

Laser system with mechanically-robust monolithic fused planar waveguide (PWG) structure

A method includes obtaining a substrate having at least one exposed metal surface. The method also includes electro-depositing metal onto the at least one exposed metal surface of the substrate and around at least a portion of an optical fiber to secure the optical fiber to the substrate. The substrate and the electro-deposited metal are configured to remove heat from the optical fiber. The method could further include electro-depositing metal around a sacrificial material and removing the sacrificial material to form at least one cooling channel through the electro-deposited metal. The optical fiber could include a polymer coating, where a portion of the polymer coating is removed at an end of the optical fiber. The substrate and the electro-deposited metal could be faceted at an input of the optical fiber and at an output of the optical fiber. The optical fiber could have a coiled arrangement on the substrate.

Thermal management for high-power optical fibers

Described herein are devices and techniques for suppressing parasitic modes in planar waveguide amplifier structures. One or more of the side and end facets of a planar waveguide amplifier are angled with respect to a fast axis defined in a transverse plane perpendicular to a core region. A relationship between glancing in-plane angles of incidence and threshold bevel angles &#x3b8;can be used to select side bevel angles &#x3b8;to suppress parasitics by redirecting amplified spontaneous emission (ASE) from the core. It is possible to select the one or more bevel angles &#x3b8;to be great enough to substantially redirect all but ballistic photons of any guided modes, effectively narrowing a numerical aperture of the planar waveguide amplifier along a slow axis, defined in a transverse plane perpendicular to the fast axis. Beneficially, such improvements can be realized for three part waveguide structures (e.g., cladding-core-cladding), with substantially smooth edge facets.

Suppression of amplified spontaneous emission (ASE) within laser planar waveguide devices

In various embodiments, an optical element, e.g., an optical fiber, may be configured to compensate for thermal lensing. For example, thermal lensing may be caused by light power dissipation within an optical fiber, which may include a fiber core that guides amplified light along the longitudinal dimension of the fiber core. Thermal lensing from a thermally induced change in material refractive index as a function of position along dimensions perpendicular to the fiber's longitudinal dimension may be at least partially compensated or offset when light is guided by the fiber core by a designed-in effective refractive index profile selected such that the designed-in material refractive index of the fiber core changes as a function of transverse position within the fiber core, or by selection of a favorable cross-sectional core shape in a plane perpendicular to the longitudinal dimension of the fiber core.

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Santa Monica, CA, United States of America

Friedrich P Strohkendl