Abstract: The present invention is a method for real-time predictive laser beam propagation through various atmospheric conditions and over predetermined distances. The invention includes loading input parameters into an embedded control scheme of a laser system. A prediction of one or more laser beam parameters is generated and a computational error is quantified for the generated laser beam parameters. One or more parameters for the laser system are then chosen based on the prediction and based on the quantified computational error. The chosen parameters are within a predetermined tolerance. A laser system is then built or adjusted using the one or more chosen parameters.

Abstract: The present invention is a method for real-time predictive laser beam propagation through various atmospheric conditions and over predetermined distances. The invention includes loading input parameters into an embedded control scheme of a laser system. A prediction of one or more laser beam parameters is generated and a computational error is quantified for the generated laser beam parameters. One or more parameters for the laser system are then chosen based on the prediction and based on the quantified computational error. The chosen parameters are within a predetermined tolerance. A laser system is then built or adjusted using the one or more chosen parameters.

Abstract: A system for combining multiple fiber amplifiers, or multiple fiber amplifiers. The system includes a fiber combiner with multiple cores for connecting with the multiple fiber amplifiers and for combining the beams of the fiber amplifiers into a single beam. The fiber amplifiers are aligned, tapered, and stretched. A method for combining fiber amplifiers includes emitting a beam from a tapered fiber combiner and transmitting and coupling a portion of the emitted beam back into the fiber combiner via a feedback fiber. The transmission and coupling of the feedback fiber includes mixing the feedback fiber with the output of an auxiliary laser and boosting the feedback fiber by a pre-amplifier. The feedback fiber is split into a plurality of beams by a fiber splitter. The beams are fed into an array of fiber amplifiers and combined with output of the individual fiber amplifiers to form the tapered fiber combiner.

Abstract: A system and a method for coupling multiple pump light beams to an active fiber. The system including an inverted conical disk, concave lens or glass wedge, an active fiber placed in a center of the inverted conical disk (or concave lens) or at a bottom facet of the glass wedge and a plurality of pump light sources. The system further includes a plurality of lenses for focusing pump light beams from pump light sources towards a side of the inverted conical disk, concave lens or glass wedge, wherein the inverted conical disk, concave lens or glass wedge, couples the pump light beams into the active fiber. A method for coupling multiple pump light beams to an active fiber. The method includes providing an inverted conical disk, concave lens or glass wedge. The method further includes providing an active fiber in approximately the center of the inverted conical disk (or concave lens) or at a bottom facet of the glass wedge.

Abstract: A system for combining multiple fiber amplifiers, or multiple fiber amplifiers. The system includes a fiber combiner with multiple cores for connecting with the multiple fiber amplifiers and for combining the beams of the fiber amplifiers into a single beam. The fiber amplifiers are aligned, tapered, and stretched. A method for combining fiber amplifiers includes emitting a beam from a tapered fiber combiner and transmitting and coupling a portion of the emitted beam back into the fiber combiner via a feedback fiber. The transmission and coupling of the feedback fiber includes mixing the feedback fiber with the output of an auxiliary laser and boosting the feedback fiber by a pre-amplifier. The feedback fiber is split into a plurality of beams by a fiber splitter. The beams are fed into an array of fiber amplifiers and combined with output of the individual fiber amplifiers to form the tapered fiber combiner.

Abstract: A system and a method for coupling multiple pump light beams to an active fiber. The system including an inverted conical disk, concave lens or glass wedge, an active fiber placed in a center of the inverted conical disk (or concave lens) or at a bottom facet of the glass wedge and a plurality of pump light sources. The system further includes a plurality of lenses for focusing pump light beams from pump light sources towards a side of the inverted conical disk, concave lens or glass wedge, wherein the inverted conical disk, concave lens or glass wedge, couples the pump light beams into the active fiber. A method for coupling multiple pump light beams to an active fiber. The method includes providing an inverted conical disk, concave lens or glass wedge. The method further includes providing an active fiber in approximately the center of the inverted conical disk (or concave lens) or at a bottom facet of the glass wedge.

Abstract: An apparatus and method for high power amplification in a multimode fiber amplifier. The apparatus includes a diffraction limited low power laser, a multimode fiber amplifier, and a lens. The multimode fiber amplifier is coupled to the low power laser to amplify the low power laser output. The multimode fiber amplifier has a length that is set to a phase-matching length at which the transverse modes of the multimode fiber amplifier are in phase. The lens is coupled to the multimode fiber amplifier and outputs a kilowatt (KW)-level, diffraction-limited output beam from the multimode fiber amplifier.

Abstract: A system and method for combining plural low power light beams into a coherent high power light beam. Optical amplifiers transmit a plurality of light beams propagating at a common wavelength through an array of optical fiber emitters. Each constituent beam is emitted from the array at a different propagation angle, collimated, and incident on a diffractive optical element operating as a beam combiner such that incident beams when properly phased and located are combined into a coherent beam at a desired diffraction order. A beam splitter or a periodic sampling grating on the diffractive optical element directs a low power sample beam to a spatial filter passing resonant mode output back to the optical amplifiers in a ring laser configuration thereby passively synchronizing phases of the constituent beams to maximize combination efficiency of the coherent beam.

Abstract: An optical fiber amplifier array and related method, in which high beam quality is achieved by varying the frequency of an input signal applied to all of the fiber amplifiers, to locate a frequency at which the amplifiers produce nearly coherent optical outputs. In spite of statistical variations in length and other factors among the fibers, there are frequencies at which the amplifiers produce nearly coherent outputs. In the control system of the invention, the input signal frequency is scanned across a selected narrow range and the beam quality is monitored by measuring on-axis far-field output beam intensity. The frequency is scanned until the beam intensity exceeds a selected threshold, and then the frequency is held constant until the beam intensity falls below a second selected threshold.

Abstract: An image detection system includes a multimode fiber amplifier. The multimode fiber amplifier includes a core configured to receive an input image that includes a plurality of input beams spanning a range of incidence angles and to propagate at least some of the input beams as different ones of a plurality of transverse modes along the core. The multimode fiber amplifier provides an amplified image at an output facet thereof corresponding to the input image. A focal plane detector includes an array of detectors arranged to receive different portions of the amplified image.

Abstract: An optical fiber amplifier array and related method, in which high beam quality is achieved by varying the frequency of an input signal applied to all of the fiber amplifiers, to locate a frequency at which the amplifiers produce nearly coherent optical outputs. In spite of statistical variations in length and other factors among the fibers, there are frequencies at which the amplifiers produce nearly coherent outputs. In the control system of the invention, the input signal frequency is scanned across a selected narrow range and the beam quality is monitored by measuring on-axis far-field output beam intensity. The frequency is scanned until the beam intensity exceeds a selected threshold, and then the frequency is held constant until the beam intensity falls below a second selected threshold.

Abstract: A method passively locks and phases an array of fiber amplifiers in a fiber amplifier system that emits a beam, such as a laser beam. The method locks the fiber amplifiers so that the fiber amplifiers operate at same or similar frequencies. The method samples a small portion of the emitted beam in a far-field around a central lobe on an optical axis and then couples this portion of emitted beam back into the array of fiber amplifiers. The fiber amplifiers may be phased so that the emitted beam concentrates its energy around the central lobe in the far-field. Phasing may be achieved by using an aperture, for example, to restrict the portion of the emitted beam to be coupled back to a restricted region around the optical axis.

Abstract: A method passively locks and phases an array of fiber amplifiers in a fiber amplifier system that emits a beam, such as a laser beam. The method locks the fiber amplifiers so that the fiber amplifiers operate at same or similar frequencies. The method samples a small portion of the emitted beam in a far-field around a central lobe on an optical axis and then couples this portion of emitted beam back into the array of fiber amplifiers. The fiber amplifiers may be phased so that the emitted beam concentrates its energy around the central lobe in the far-field. Phasing may be achieved by using an aperture, for example, to restrict the portion of the emitted beam to be coupled back to a restricted region around the optical axis.

Abstract: An apparatus and method for high power amplification in a multimode fiber amplifier. The apparatus includes a diffraction limited low power laser, a multimode fiber amplifier, and a lens. The multimode fiber amplifier is coupled to the low power laser to amplify the low power laser output. The multimode fiber amplifier has a length that is set to a phase-matching length at which the transverse modes of the multimode fiber amplifier are in phase. The lens is coupled to the multimode fiber amplifier and outputs a kilowatt (KW)-level, diffraction-limited output beam from the multimode fiber amplifier.

Abstract: A multimode optical fiber has a core that includes radially dependent dopant materials to provide a desired refractive index profile and a desired Raman gain coefficient profile. A laser diode pump laser array provides high brightness light that is launched into the fiber and is subject to maximum Raman gain along the optical axis, thereby favoring the lowest order mode of the fiber, discriminating against higher order modes and providing a high brightness, diffraction limited output. The fiber can be incorporated into oscillators, amplifiers and other optical devices.