Imra America, Inc.

Clemson University

Hokkaido University

Nufern

Liang Dong

Martin E Fermann

William S Wong

Xiang Peng

Libin Fu

Brian Thomas

Hugh McKay

Andrius Marcinkevicius

Donald J Harter

Ingmar Hartl

Jun Li

Shigeru Suzuki

Kunimasa Saitoh

Bryce Neilson Samson

Kanxian Wei

Turghun Matniyaz

Brian K Thomas

High-power, highly efficient 3-level system fiber lasers are described. The lasers can operate at an average power of about 50W or greater with an efficiency of about 60% or greater with low diffraction limited mode quality. The lasers incorporate an all-solid photonic bandgap fiber that includes a large core (20 micrometers or greater), a high core/clad ratio (greater than 15%), and a waveguide cladding designed to define a transmission band to suppress the 4-level system of the gain medium through determination of the node size of individual nodes of a cladding lattice.

Three-level system fiber lasers incorporating an all-solid photonic bandgap fiber

Embodiments of optical fiber may include cladding features that include a material (e.g., fluorine-doped silica glass) that may produce a very low relative refractive index difference with respect to cladding material in which the cladding features are disposed. This relative refractive index difference may be characterized by (n&#x2212;n)/n, where nis the index of refraction of the cladding material in which the cladding features are included, and nis the index of refraction of the cladding features. In certain embodiments, the relative refractive index difference may be less than about 4.5&#xd7;10. In various embodiments, the configuration of the cladding features including, for example, the size and spacing of the cladding features, can be selected to provide for confinement of the fundamental mode yet leakage for the second mode and higher modes, which may provide mode filtering, single mode propagation, and/or low bend loss.

Glass large-core optical fibers

Holey fibers provide optical propagation. In various embodiments, a large core holey fiber comprises a cladding region formed by large holes arranged in few layers. The number of layers or rows of holes about the large core can be used to coarse tune the leakage losses of the fundamental and higher modes of a signal, thereby allowing the non-fundamental modes to be substantially eliminated by leakage over a given length of fiber. Fine tuning of leakage losses can be performed by adjusting the hole dimension and/or spacing to yield a desired operation with a desired leakage loss of the fundamental mode. Resulting holey fibers have a large hole dimension and spacing, and thus a large core, when compared to traditional fibers and conventional fibers that propagate a single mode. Other loss mechanisms, such as bend loss and modal spacing can be utilized for selected modes of operation of holey fibers.

Large core holey fibers

Various embodiments include large cores fibers that can propagate few modes or a single mode while introducing loss to higher order modes. Some of these fibers are holey fibers that comprise cladding features such as air-holes. Additional embodiments described herein include holey rods. The rods and fibers may be used in many optical systems including optical amplification systems, lasers, short pulse generators, Q-switched lasers, etc. and may be used for example for micromachining.

Single mode propagation in fibers and rods with large leakage channels

Embodiments of optical fiber may include cladding features that include a material (e.g., fluorine-doped silica glass) that may produce a very low relative refractive index difference with respect to cladding material in which the cladding features are disposed. This relative refractive index difference may be characterized by (n-n)/n, where nis the index of refraction of the cladding material in which the cladding features are included, and nis the index of refraction of the cladding features. In certain embodiments, the relative refractive index difference may be less than about 4.5&#xd7;10. In various embodiments, the configuration of the cladding features including, for example, the size and spacing of the cladding features, can be selected to provide for confinement of the fundamental mode yet leakage for the second mode and higher modes, which may provide mode filtering, single mode propagation, and/or low bend loss.

High power parallel fiber arrays for the amplification of high peak power pulses are described. Fiber arrays based on individual fiber amplifiers as well as fiber arrays based on multi-core fibers can be implemented. The optical phase between the individual fiber amplifier elements of the fiber array is measured and controlled using a variety of phase detection and compensation techniques. High power fiber array amplifiers can be used for EUV and X-ray generation as well as pumping of parametric amplifiers.

High power parallel fiber arrays

Various embodiments described herein include rare earth doped glass compositions that may be used in optical fiber and rods having large core sizes. Such optical fibers and rods may be employed in fiber lasers and amplifiers. The index of refraction of the glass may be substantially uniform and may be close to that of silica in some embodiments. Possible advantages to such features include reduction of formation of additional waveguides within the core, which becomes increasingly a problem with larger core sizes.

Rare earth doped and large effective area optical fibers for fiber lasers and amplifiers

Photonic bandgap fibers are described that can be solid across the core and clad and have a large core diameter with little loss in the fundamental mode. In addition, the mode loss of the higher order modes can be much greater than that of the fundamental mode, providing high power fibers with high effective mode area. Excellent single mode output can be obtained from the fibers in length scale close to what is required for fiber laser and amplifiers.

High power optical fibers

Embodiments of auto-cladded optical fibers are described. The fibers may have a refractive index profile having a small relative refractive index change. For example, the fiber may include an auto-cladded structure having, e.g., a trough or gradient in the refractive index profile. A beam of light propagating in the fiber may be guided, at least in part, with the auto-cladded structure. In some embodiments, the optical fiber may be all glass. In some embodiments, the optical fiber may include a large-core or an ultra large-core.

Growing community of inventors

Clemson, SC, United States of America

Liang Dong