Amoco Corporation

Coherent, Inc.

Scientific-atlanta, Inc.

Atx Telecom Systems, Inc.

Iolon, Inc.

Fibercore Limited

Douglas W Anthon

Sergei V Govorkov

John H Clark

Luis A Spinelli

Donald Lee Sipes, Jr

George J Dixon

Timothy C Munks

Jill D Berger

James H Fisher

Pedram Akhavan-Leilabady

Jay Michael Ingalls

John D Minelly

David A King

Man Cheung

Sol Peter DiJaili

Darwin K Serkland

Stephen J Hrinya

Michael G Ressl

Alexander Tselikov

Alan A Fennema

Prem Jothipragasam Kumar

Kevin L Sweeney

Leo F Johnson

Fedor A Ilkov

Michael R Keur

William L Kath

Gregory J Lukas

Janet E Townsend

Stephen G Grubb

Howard S Lee

Peter Maton

Alan T Eggleston

Gregory R Ristau

Chris Emslie

Daniel M Ou

William L Barnes

Timothy J Pier

Daniel M Grasso

Donald L Sipes

Ashley Speed

Laser apparatus includes a laser the output of which is formed into a collimated beam then focused into a transport fiber at a particular effective numerical aperture. A parallel plate is located in the collimated beam and can be variably inclined with respect to the collimated beam for varying the effective numerical aperture of the radiation focused into the fiber. In one embodiment, a second parallel plate is located in the focused beam, and can be variably inclined with respect to the focused beam for aligning the focused beam with the optical fiber.

Fiber-coupled laser with adjustable beam-parameter-product

A CW fiber-laser includes a gain fiber having a reflector proximity-coupled to one end, with the other end left uncoated. A laser resonator is defined by the reflector and the uncoated end of the gain-fiber. Pump-radiation from two fast-axis diode-laser bar stacks is combined and focused into the uncoated end of the gain-fiber for energizing the fiber. Laser radiation resulting from the energizing is delivered from the uncoated end of the gain-fiber and separated from the pump-radiation by a dichroic mirror.

High-power CW fiber-laser

A CW ytterbium-doped fiber-laser includes a gain-fiber having a reflector proximity-coupled to one end, with the other end left uncoated. A laser resonator is defined by the reflector and the uncoated end of the gain-fiber. Pump-radiation from fast-axis diode-laser bar-stacks emitting at 915 nm and 976 nm is combined and focused into the uncoated end of the gain-fiber for energizing the fiber. Laser radiation resulting from the energizing is delivered from the uncoated end of the gain-fiber and separated from the pump-radiation by a dichroic mirror.

Arrangements for combination and fast-axis alignment of fast-axes of diode-laser beams are disclosed. Alignment arrangements include providing each diode-laser with a corresponding alignable fast-axis collimating lens, providing individually alignable mirrors for steering an re-orienting beams from each diode-laser, and providing single diode-laser slab-modules in which the diode-laser beams can be pre-aligned to a common propagation-axis direction, and in which edges and surfaces of the slabs can be used to align the fast and slow-axes of the beams. Beam combination methods include combination by dichroic elements, polarization-sensitive elements, and optical fiber bundles.

High power and high brightness diode-laser array for material processing applications

An apparatus for filtering an input beam of light to produce an output beam of light is provided. The apparatus facilitates tuning an input beam of light to a desired wavelength by directing the input beam of light, via a mirror, onto a diffractive optical element and returning the diffracted portion of the input beam of light as an output beam of light. The apparatus may also include a polarization recovery element adapted for receiving the input beam of light and outputting a first and second spatially offset beam of polarized light. The apparatus may also be configured as a tunable receiver by utilizing a detector to detect a characteristic of a filtered output beam. The output beam may be additionally filtered by a spatial filter.

Tunable optical filter, optical apparatus for use therewith and method utilizing same

An apparatus and method for controlling the phase of a tunable laser is provided. Stabilization of the mode of a laser beam is provided as the laser is tuned to a target frequency. For one embodiment, a laser generates a reference beam and an output beam. The power of each of beam is measured by optical detectors, and a ratio thereof is utilized to detect when a mode hop occurs as the laser is coarsely tuned. The average of the pre and post mode hop ratios is utilized as a control setpoint while finely tuning the laser to the target frequency. Wavelength lockers, optical power dividers and optical detectors are utilized to determine power levels of the reference and output beams while also monitoring frequency characteristics thereof. A control unit utilizes the outputs from the wavelength locker to control the operation of the extended cavity laser during and after tuning.

Apparatus and method for phase control of tunable external cavity lasers

Systems and methods are described for the construction of micro-optical couplers incorporating optical tapers to reshape multimode optical inputs. Incorporating tapers allows the spatial properties of the multimode inputs to be adjusted to match to the spatial properties of the output fiber, even in systems that are limited to unity-magnification imaging optics. In an exemplary embodiment, a larger-core multimode fiber and a smaller-core double-clad fiber are glued into a glass capillary, with the multimode fiber tapering to a smaller diameter inside the capillary. Polishing the capillary to expose the taper gives a multimode core that is smaller than the double-clad core. Imaging with unity magnification through a GRIN lenses and a dichroic reflector transfers the multimode input efficiently to the double-clad fiber with greater efficiency than would have been possible with the same optics and an untapered fiber. The dichroic reflector is transparent to a second singlemode signal input, which is collimated by a second GRIN lens and coupled to through the reflector to the core of the double-clad fiber. An isolator may be included in the signal beam path, and the double-clad fiber may be replaced by a double-clad gain fiber.

Micro-optic coupler incorporating a tapered fiber

An optical fiber ( ) made with a central core ( ), a first cladding layer ( ), and a second cladding layer ( ) having a series of perturbations or irregularities formed into the otherwise generally circular outer boundary of the first cladding layer ( ). The irregularities in the first cladding layer ( ) interrupt the propagation of skew rays and encourage coupling into the core ( ).

Optical fiber with irregularities at cladding boundary

Systems and methods for suppressing cladding modes at the signal wavelength in an optical fiber system utilizing an optical amplifier without perturbing the pump wavelength. An outer cladding of the gain fiber is removed providing a short section of a single mode fiber that does not guide the higher order modes, thus attenuating the higher order modes. Therefore, this system eliminates unwanted noise. In an embodiment, the modes are filtered at the end of the gain section of the optical fiber before splicing to an input fiber. Hydro florate etching can be utilized to remove the outer cladding. The resulting fiber maintains fundamental mode propagation and no mode mixing occurs while losing the higher order modes eliminating the noise.

Noise reduction technique for cladding pumped optical amplifiers

A highly stable soliton source uses a bulk Er/Yb glass laser which operates in two longitudinal modes of the laser cavity with substantially identical amplitudes to generate beat modulation. The beat modulation is then passed through a pulse compression fiber which compresses the beat modulation into a train of soliton pulses. Because the beat modulation is between two modes of the same laser cavity, the soliton pulse train generated is highly stable with low timing jitter.

High stability soliton source

The laser device of the present invention includes a high-power, fiber-coupled optical source (FIG. 1) having a broad area laser diode (10) with a high reflective coating at its rear facet (12), coupling optics (20), and an optical fiber (30) having fiber grating (32). The fiber grating (32) serves to reflect a portion of the optical beam back to the broad area laser diode (10), thereby stabilizing the wavelength of the optical beam. The fiber grating (32) and the rear facet (12) of the broad area laser diode (10) serve as nodes for an external resonator, thereby limiting the diffraction of the optical beam. The effects of wavelength fluctuation and beam diffraction are reduced together using minimal mechanical components.

Fiber grating feedback stabilization of broad area laser diode

A multi-functional optical isolator that couples radiation from a plurality of input fibers to a plurality of output fibers such that an optical beam emitted from any particular input fiber is transmitted only to its corresponding output fiber. Additionally, an optical beam emitted in the reverse direction from any output fiber is not transmitted back into any of the input or output fibers. The multi-functional optical isolator includes a first focusing lens that collimates the optical radiation emitted from the input fibers and causes them to pass through an optical isolator. The optical isolator has polarizing elements and a magneto-optic polarization rotator. A second focusing lens focuses the optical beams into the output fibers such that the optical radiation from each input fiber is coupled to its corresponding output fiber. Additional off-axis optical elements at other wavelengths may be used for providing bulk-optic coupling of a pump light into a single-mode or multi-mode core of a doped fiber. A vee-shaped isolator with a high reflector in the isolated beam path is possible and provides for additional beams coupled through the reflector.

Multi-functional optical isolator

A monolithic solid state laser structure is used to construct erbium lasers that are insensitive to external pressure changes and vibrations, and have improved cooling of the gain medium and reduced thermal lensing effect. In the monolithic laser structure, the gain medium is separated from an optically transmissive plate on one side and a wave plate on the other side by spacers to form narrow air gaps which provide effective cooling of the gain medium and reduced the thermal lensing effect. Such an arrangement is further combined with a pressure-insensitive Brewster polarizer, such as a solid Brewster polarizer or a pressure-sealed Brewster plate, to form a pressure-insensitive laser cavity. The wave plate cooperates with the Brewster polarizer to select the wavelength of the solid state laser.

Multi-element monolithic solid state laser

Two solid state laser structures are provided which are optimized for multimode operation. The first laser structure has a plurality of normal incidence optically transmissive surfaces in the laser cavity. The most reflective one of those normal incidence surfaces is disposed at the optical center of the laser cavity. The gain medium is centered in the subcavity defined by a cavity mirror and the optical center. In the second laser structure, there are no normal incidence surface in the laser cavity, and the gain medium is disposed at the optical center of the laser cavity. The laser structures are employed to construct erbium glass lasers which are not only optimized for multimode operation but also have effective cooling of the gain medium and minimized thermal lensing effect.

Solid state laser optimized for multimode operation

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Wheaton, IL, United States of America

Douglas W Anthon