Bae Systems Information and Electronic Systems Integration Inc.

Nufern

Daniel J Creeden

Peter Ketteridge

Benjamin R Johnson

Peter A Budni

John C McCarthy

Scott D Setzler

York E Young

Robert T Carlson

Chris L Willis

Joseph M Owen

David Paul Kelly

Brant M Kaylor

Paul R Moffitt

Hermanus Stephanus Pretorius

Rick L Thompson

Robert C Guyer

Katherine J Snell

Adam J Marcinuk

Aaron W Bennett

Kenneth Dinndorf

Julia R Limongelli

The present disclosure relates to optical fiber amplifying systems having operability at a wide variety of ambient temperatures and to methods for using them. One aspect of the disclosure is an optical fiber system configured to provide amplified radiation. The system includes an active optical fiber; a plurality of grating-locked pump sources, each having an output optically coupled to the active optical fiber; one or more temperature sensors, configured to measure a temperature associated with one or more of the grating-locked pump sources; and a control system configured to accept measurements from the one or more temperature sensors and, for a desired total pump power output, to provide to one or more of the grating-locked pump sources a set of drive currents suitable to provide the desired total pump power output.

Optical fiber amplifier system and methods of using same

A phase controller for rapid, accurate, stable phase shifting of a continuous wave (cw) laser output combines and adjusts reference paths from before and after an EOPM to obtain maximum constructive interference when the EOPM control voltage is zero. A control voltage V for maximum destructive interference is then determined and regulated to produce and maintain a 180 degree phase shift. The output phase can then be shifted by switching the control voltage to the output of a voltage shifter that shifts V by a specified percentage. The phase shifter can divide the control voltage in half to provide a 90 degree phase shift. The cw laser can function as a seed to a pulsed laser, thereby controlling the pulse phases. Quadrature phase laser pulse pairs can be used for quadrature LiDAR detection. Embodiments include a plurality of voltage shifters for 4-phase quadrature shifting and/or shifting between arbitrary phase values.

Apparatus and method for producing rapid and accurate laser phase shifts

In the method for generating blue laser light with high optical and electrical efficiency, wherein the improvement comprises the step of using a phosphate glass photonic crystal fiber rod as a gain medium.

Phosphate photonic crystal fiber and converter for efficient blue generation

A fiber optic geometric isolator is disclosed which is inserted between two cascaded, high-power fiber optic lasers and, in conjunction with a cladding mode stripper, provides improved optical Isolation between the two fiber optic lasers while maintaining highly-efficient laser operation. The isolator achieves this without the need for electromagnetic isolation between the two cascaded lasers. The isolator is an optical fiber designed to operate as a monolithic, continuous waveguide to enable a specific mode-coupling condition that converts the light of a first laser to that of a second, cascaded laser, with the light moving from the core of the first laser to both the core and the cladding of the second laser.

Geometric isolator providing isolation between resonantly pumped cascaded laser

A laser system and method of use are provided in which the laser system may include a fiber laser oscillator and rare earth doped piece of optical fiber which may absorb unused pump light which is unabsorbed in the oscillator.

Pump recycling integrated amplifier

In the method of generating high power light with high efficiency and low thermal loading, the improvement comprising the steps of resonantly pumping a first thulium-doped fiber laser with a second thulium-doped fiber last, said second thulium-doped fiber laser having a shorter wavelength than said first thulium-doped fiber laser.

Highly efficient thulium doped fiber laser

The system and method for reducing Yb to Er bottlenecking in a single frequency Er:Yb-doped fiber laser amplifier. The system is pumped off peak at about 935-955 nm. The off-peak pumping reduces bottlenecking and increases the optical and slope efficiency of the system by about 10% as compared to an EYDFA system pumped on-peak.

Reduction of Yb-to-Er bottlenecking in co-doped fiber laser amplifiers

Techniques are disclosed for monitoring parameters in a high power fiber laser or amplifier system without adding a tap coupler or increasing fiber length. In some embodiments, a cladding stripper is used to draw off a small percentage of light propagating in the cladding to an integrated signal parameter monitor. Parameters at one or more specific wavelengths (e.g., pump signal wavelength, signal/core signal wavelength, etc) can be monitored. In some such cases, filters can be used to allow for selective passing of signal wavelength to be monitored to a corresponding parameter monitor. The filters can be external or may be integrated into a parameter monitor package that includes cladding stripper with integrated parameter monitor. Other parameters of interest (e.g., phase, wavelength) can also be monitored, in addition to, or as an alternative to power. Numerous configurations and variations will be apparent in light of this disclosure (e.g., system-on-chip).

Integrated parameter monitoring in a fiber laser/amplifier

Techniques are disclosed for improving pump absorption and efficiency for fiber lasers and amplifiers, for instance. In some embodiments, the techniques are implemented by applying a partially reflective coating on a fiber end-face to double-pass any unabsorbed or otherwise excess pump light in the cladding of a fiber. While being reflective to pump wavelengths, the coating can be non-reflective at the lasing wavelength, so as to avoid unwanted feedback into the system. The benefits of this approach include that excess pump power can be effectively utilized to add more power to the laser output. In addition, the double-pass technique allows for the use of a shorter fiber length, which in turn allows for more compact system designs, saves on material costs, and facilitates manufacturability.

Pump absorption and efficiency for fiber lasers/amplifiers

A broadband spectral power generator in a multimode optical fiber utilizes a standard multimode fiber that is coiled. A plate is placed on the coiled fiber and a force is applied to compresses the coiled fiber and thereby increase the interactions between the compressed windings and induce modal mixing and birefringence in the fiber. In addition, the compression causes additional non-linear processes to be excited and occur in the compressed fiber coil to generate more broadband light. This allows for better 'mixing' of the spatial beam in the multimode fiber coil and allows for the various modes to overlap. The multimode fiber coil is made of silica, silicate, germinate, phosphate, fluoride, chalcogenide, or telluride. The compressed coiled fiber may be driven by a laser providing more than one wavelength output and this greatly increases the amount of nonlinear mixing in the fiber for a greatly enhanced spectral coverage.

Generating broadband spectral power in multimode optical fibers

Techniques and architecture are disclosed for controlling the temperature of a fiber laser system. In some embodiments, a single thermoelectric cooler (TEC) may be utilized to control the temperature of multiple system components. In some embodiments, a TEC may be physically/thermally coupled to a laser diode, which in turn may be physically/thermally coupled with a mounting plate to which one or more fiber grating holders are physically/thermally coupled, and an optical fiber that is operatively coupled with the laser diode may be physically/thermally coupled with the one or more fiber grating holders. In some embodiments, this may provide a thermal pathway/coupling between the optical fiber (e.g., its fiber grating(s)), and the TEC. In some embodiments, this may reduce/minimize the quantity of temperature control components, reduce system size/complexity, increase system dependability, and/or increase system performance/efficiency. Numerous configurations and variations will be apparent in light of this disclosure.

Temperature control of a fiber laser system

In the method for processing a signal light from free-space by amplifying said signal for free-space optical communications, wherein the improvement includes the steps of (a) pre-amplifying said signal light with low noise; and (b) coupling said signal light into a multimode filter which reduces coupling losses compared to single mode filters.

Multimode optical amplifier as a receiver pre-amplifier for free-space optical communications

A system and method for efficiently combining multiple laser beams into a single frequency by invoking stimulated Brillouin scattering (SBS) in a dual core optical fiber is disclosed. The method and apparatus essentially becomes a brightness converter for the input laser beams. An SRS seed is generated in a long length of fiber or by a diode and is launched into the back-end of the SBS combining optical fiber. Various single-frequency pump beams are launched into the front-end of the same fiber. The seed acts to lower a threshold for SBS in the fiber, thus invoking the nonlinearity. Provided the various pump beams are close in frequency and seed/pump modes overlap, each acts to amplify the seed through the nonlinear SBS process, providing an output signal which is brighter than the combined pump beams.

Method for beam combination by seeding stimulated brillouin scattering in optical fiber

A combined large mode area, fiber cable amplifier and laser beam transport fiber cable is disclosed that transports laser beams output from a compact, high power, solid state laser to remote locations while improving the beam quality and amplifying the beam to compensate for losses in the fiber cable. The fiber cable is clad and is cladding pumped to compensate for the losses in the fiber cable.

Growing community of inventors

Nashua, NH, United States of America

Daniel J Creeden