Abstract: A method of stabilizing a fiber Bragg grating (FBG) disposed in a thermomechanical housing included performing an initialization process including measuring a transmission ratio at a plurality of FBG temperatures between an initial and final temperature, determining a maximum transmission ratio, and changing the temperature of the FBG until the transmission ratio equals a target transmission ratio. The method also includes performing an operation process including (a) measuring the transmission ratio, (b) adjusting the FBG temperature to align the measured transmission ratio with the predetermined fraction of the maximum transmission ratio, and (c) iteratively performing (a) and (b).

Abstract: A method of stabilizing a fiber Bragg grating (FBG) disposed in a thermomechanical housing included performing an initialization process including measuring a transmission ratio at a plurality of FBG temperatures between an initial and final temperature, determining a maximum transmission ratio, and changing the temperature of the FBG until the transmission ratio equals a target transmission ratio. The method also includes performing an operation process including (a) measuring the transmission ratio, (b) adjusting the FBG temperature to align the measured transmission ratio with the predetermined fraction of the maximum transmission ratio, and (c) iteratively performing (a) and (b).

Abstract: A system for stabilizing optical parameters of a fiber Bragg grating (FBG) includes a mechanical mount, a heating element coupled to the mechanical mount, and a base plate coupled to the heating element. The base plate comprises a longitudinal groove. The system also includes a fiber anchor coupled to the mechanical mount and a fiber including the FBG mechanically attached to the fiber anchor. The FBG of the fiber is disposed in the longitudinal groove.

Abstract: A spectral beam combining system includes a plurality of input fibers and a prism having a curved input surface. The plurality of input fibers are attached to the curved input surface. The spectral beam combining system also includes an immersion grating defined on a second surface of the prism, a protective cap disposed over the immersion grating, and an output surface.

Abstract: A multi-wavelength laser system includes a first fiber laser having a first cavity mirror and a first output coupler, a first optical coupler configured to receive light from the first output coupler, a second fiber laser having a second cavity mirror and a second output coupler, and a second optical coupler configured to receive light from the second output coupler. The multi-wavelength laser system also includes a spectral beam combiner configured to receive first output light from the first optical coupler, receive second output light from the second optical coupler, combine the first output light and the second output light, and form a multi-wavelength output beam.

Abstract: A system for stabilizing optical parameters of a fiber Bragg grating (FBG) includes a mechanical mount, a heating element coupled to the mechanical mount, and a base plate coupled to the heating element. The base plate comprises a longitudinal groove. The system also includes a fiber anchor coupled to the mechanical mount and a fiber including the FBG mechanically attached to the fiber anchor. The FBG of the fiber is disposed in the longitudinal groove.

Abstract: An immersion grating includes a dielectric substrate having an incident light surface and a second surface opposing the incident light surface. The dielectric substrate is characterized by a substrate index of refraction. The immersion grating also includes at least one dielectric layer coupled to the second surface of the dielectric substrate. The at least one dielectric layer is characterized by a layer index of refraction greater than the substrate index of refraction. The immersion grating further includes a periodic structure formed in the at least one dielectric layer. The immersion grating is characterized by a diffraction efficiency greater than 99% over a wavelength range from 1041 nm to 1066 nm.

Abstract: An optical fiber, such as in some instances a high-power, diode-pumped, dual-clad, ytterbium-doped fiber amplifier (YDFAs), having a fundamental mode and at least one higher order mode, wherein the higher order mode or modes have mode areas that are substantially larger than a mode area of the fundamental mode.

Abstract: A spectral beam combining system includes a plurality of input fibers and a prism having a curved input surface. The plurality of input fibers are attached to the curved input surface. The spectral beam combining system also includes an immersion grating defined on a second surface of the prism, a protective cap disposed over the immersion grating, and an output surface.

Abstract: A spectral beam combining system includes a plurality of input fibers and a prism having a curved input surface. The plurality of input fibers are attached to the curved input surface. The spectral beam combining system also includes an immersion grating defined on a second surface of the prism, a protective cap disposed over the immersion grating, and an output surface.

Abstract: A spectral beam combining system includes a plurality of input fibers and a prism having a curved input surface. The plurality of input fibers are attached to the curved input surface. The spectral beam combining system also includes an immersion grating defined on a second surface of the prism, a protective cap disposed over the immersion grating, and an output surface.

Abstract: A multispectral beam combiner includes a prism body having an output surface, a fiber entry block attached to the prism body, and a plurality of input fibers attached to the fiber entry block. Each of the plurality of input fibers is operable to support a different wavelength. The multispectral beam combiner also includes a collimator attached to the prism body. The collimator is operable to reflect and collimate light propagating from the fiber entry block. The multispectral beam combiner further includes an immersion grating operable to diffract light propagating from the collimator. The output surface of the prism body is operable to pass light propagating from the immersion grating.

Abstract: An optical fiber, such as in some instances a high-power, diode-pumped, dual-clad, ytterbium-doped fiber amplifier (YDFAs), having a fundamental mode and at least one higher order mode, wherein the higher order mode or modes have mode areas that are substantially larger than a mode area of the fundamental mode.

Abstract: Methods and apparatus for spectral narrowing and wavelength stabilization of broad-area lasers, such as an apparatus including a broad-area laser source configured to emit light along an emission axis in an emission pattern extending along the emission axis, and a single-mode fiber Bragg grating, such as a single-mode core incorporating a fiber Bragg grating embedded in a core of a dual-clad fiber, the single-mode fiber Bragg grating configured to spectrally selectively reflect back light from a sub-aperture portion of the emitted light to the broad-area laser source. The single mode core having the FBG is off-axis in comparison to the central axis of the double-clad fiber and allows for frequency stabilization of the broad area laser diode output improving its performance as pump laser for a doped fiber amplifier.

Abstract: Laser signal intensity is resonantly enhanced within a laser cavity to be greater than a pump intensity. This enables the suppression of excited-state absorption and is applicable to terbium-doped fiber lasers, lambda-type materials, or other materials used in lasers. In other embodiments, ESA is suppressed by de-populating the higher excited state using a resonant cavity.

Abstract: Methods and apparatus for spectral narrowing and wavelength stabilization of broad-area lasers, such as an apparatus including a broad-area laser source configured to emit light along an emission axis in an emission pattern extending along the emission axis, and a single-mode fiber Bragg grating, such as a single-mode core incorporating a fiber Bragg grating embedded in a core of a dual-clad fiber, the single-mode fiber Bragg grating configured to spectrally selectively reflect back light from a sub-aperture portion of the emitted light to the broad-area laser source. The single mode core having the FBG is off-axis in comparison to the central axis of the double-clad fiber and allows for frequency stabilization of the broad area laser diode output improving its performance as pump laser for a doped fibre amplifier.

Abstract: Methods and apparatus for producing high power lasers with reduced speckle are provided. Fiber and solid-state lasers comprising terbium-doped lasing material are provided. Embodiments are described for increasing signal reflection bandwidth, reducing coupling and coherency of spatial modes, and equalizing gain of terbium-doped lasers for use in laser display systems. Spectral selectors are described for generating separate wavelengths within a range of interest for use in 3D laser display systems.

Abstract: Laser signal intensity is resonantly enhanced within a laser cavity to be greater than a pump intensity. This enables the suppression of excited-state absorption and is applicable to terbium-doped fiber lasers, lambda-type materials, or other materials used in lasers. In other embodiments, ESA is suppressed by de-populating the higher excited state using a resonant cavity.

Abstract: A multispectral beam combiner includes a prism body having an output surface, a fiber entry block attached to the prism body, and a plurality of input fibers attached to the fiber entry block. Each of the plurality of input fibers is operable to support a different wavelength. The multispectral beam combiner also includes a collimator attached to the prism body. The collimator is operable to reflect and collimate light propagating from the fiber entry block. The multispectral beam combiner further includes an immersion grating operable to diffract light propagating from the collimator. The output surface of the prism body is operable to pass light propagating from the immersion grating.

Abstract: An embodiment of the invention is directed to a pulse measuring system that measures a characteristic of an input pulse under test, particularly the pulse shape of a single-shot, nano-second duration, high shape-contrast optical or electrical pulse. An exemplary system includes a multi-stage, passive pulse replicator, wherein each successive stage introduces a fixed time delay to the input pulse under test, a repetitively-gated electronic sampling apparatus that acquires the pulse train including an entire waveform of each replica pulse, a processor that temporally aligns the replicated pulses, and an averager that temporally averages the replicated pulses to generate the pulse shape of the pulse under test. An embodiment of the invention is directed to a method for measuring an optical or an electrical pulse shape. The method includes the steps of passively replicating the pulse under test with a known time delay, temporally stacking the pulses, and temporally averaging the stacked pulses.