David S Welch

US Patent:

6335941, Jan 1, 2002

Filed:

May 15, 2000

Appl. No.:

09/571711

Inventors:

Stephen G. Grubb - Fremont CA
David F. Welch - Menlo Park CA
Raymond Zanoni - Fremont CA

Assignee:

SDL, Inc. - San Jose CA

International Classification:

H01S 330

US Classification:

372 6, 359179, 359341

Abstract:

A high power laser optical amplifier system for material processing comprises multiple stage fiber amplifiers with rejection of propagating ASE buildup in and between the amplifier stages as well as elimination of SBS noise providing output powers in the range of about 10 J to about 100 J or more. The system is driven with a time varying drive signal from a modulated semiconductor laser signal source to produce an optical output allowing modification of the material while controlling its thermal sensitivity by varying pulse shapes or pulse widths supplied at a desire repetition rate via modulation of a semiconductor laser signal source to the system to precisely control the applied power application of the beam relative to the thermal sensitivity of the material to be processed. The high power fiber amplifier system has particular utility in high power applications requiring process treatment of surfaces, such as polymeric, organic, ceramic and metal surfaces, e. g. , material processing, surface texturing, heat treatment, surface engraving, fine micro-machining, surface ablation, cutting, grooving, bump forming, coating, soldering, sealing, surface diffusion and surface conversion to a compound.

US Patent:

6342405, Jan 29, 2002

Filed:

May 23, 2000

Appl. No.:

09/576746

Inventors:

Jo S. Major - San Jose CA
David F. Welch - Menlo Park CA
Donald R. Scifres - San Jose CA

Assignee:

JDS Uniphase Corporation - San Jose CA

International Classification:

H01L 2100

US Classification:

438 46

Abstract:

Methods are disclosed for forming Group III-arsenide-nitride semiconductor materials. Group III elements are combined with group V elements, including at least nitrogen and arsenic, in concentrations chosen to lattice match commercially available crystalline substrates. Epitaxial growth of these III-V crystals results in direct bandgap materials, which can be used in applications such as light emitting diodes and lasers. Varying the concentrations of the elements in the III-V crystals varies the bandgaps, such that materials emitting light spanning the visible spectra, as well as mid-IR and near-UV emitters, can be created. Conversely, such material can be used to create devices that acquire light and convert the light to electricity, for applications such as full color photodetectors and solar energy collectors. The growth of the III-V crystals can be accomplished by growing thin layers of elements or compounds in sequences that result in the overall lattice match and bandgap desired.

US Patent:

6345141, Feb 5, 2002

Filed:

Dec 5, 2000

Appl. No.:

09/730168

Inventors:

Stephen G. Grubb - Columbia MD
David F. Welch - Menlo Park CA

Assignee:

SDL, Inc. - San Jose CA

International Classification:

G02B 602

US Classification:

385127, 372 6

Abstract:

A double-clad optical fiber has an inner cladding that has a torsional stress induced within it during manufacture. By rotating the fiber preform before curing of the inner cladding layer, a physical stress may be permanently imparted to the inner cladding that interacts with pump energy within the inner cladding layer to encourage mode mixing. As the cladding modes are disturbed by the stresses in the fiber, they are redirected so that the light in them intersects the core.

US Patent:

6347007, Feb 12, 2002

Filed:

Jun 2, 2000

Appl. No.:

09/586405

Inventors:

Stephen G. Grubb - Fremont CA
David F. Welch - Menlo Park CA
Raymond Zanoni - Fremont CA

Assignee:

SDL, Inc. - San Jose CA

International Classification:

H01S 300

US Classification:

35933721, 359124, 3593372, 359347, 372 18

Abstract:

A high power laser optical amplifier system for material processing comprises multiple stage fiber amplifiers with rejection of propagating ASE buildup in and between the amplifier stages as well as elimination of SBS noise providing output powers in the range of about 10 J to about 100 J or more. The system is driven with a time varying drive signal from a modulated semiconductor laser signal source to produce an optical output allowing modification of the material while controlling its thermal sensitivity by varying pulse shapes or pulse widths supplied at a desire repetition rate via modulation of a semiconductor laser signal source to the system to precisely control the applied power application of the beam relative to the thermal sensitivity of the material to be processed. The high power fiber amplifier system has particular utility in high power applications requiring process treatment of surfaces, such as polymeric, organic, ceramic and metal surfaces, e. g. , material processing, surface texturing, heat treatment, surface engraving, fine micro-machining, surface ablation, cutting, grooving, bump forming, coating, soldering, sealing, surface diffusion and surface conversion to a compound.

US Patent:

6356574, Mar 12, 2002

Filed:

Jan 29, 1999

Appl. No.:

09/240361

Inventors:

Richard R. Craig - Victoria, CA
Robert L G. Waarts - Fremont CA
David F. Welch - Menlo Park CA
John G. Endriz - Belmont CA
Dirk J. Kuizenga - Sunnyvale CA
Steven Sanders - Palo Alto CA

Assignee:

SDL, Inc. - San Jose CA

International Classification:

H01S 30933

US Classification:

372 75, 372 50

Abstract:

A multistage optical amplifier pumping system with built-in redundant reliability for lightwave communication system provides plural levels of redundancy. A first level of redundancy deals with redundancy in the form of plural primary laser diode sources for pumping a single fiber laser pump source. A second level of redundancy deals with redundancy of a plurality of fiber laser pump sources for pumping a plurality of serially connected injection signal fiber amplifiers forming the multistage amplifier system. If one of fiber pump sources should fail, increased pumping power is available from the remaining fiber pump sources via their respectively connected amplifier stages. A third level of redundancy deals with redundancy in the employment of multiple single mode laser emitters on the same chip or bar sufficiently segmented and/or electrical isolated so as not to interfere with operation of or cause failure to adjacent or neighboring emitters on the same chip or bar.

US Patent:

6404542, Jun 11, 2002

Filed:

Jul 10, 2000

Appl. No.:

09/613519

Inventors:

Mehrdad Ziari - Pleasanton CA
David F. Welch - Menlo Park CA
Vincent G. Dominic - Fremont CA
Bardia Pezeshki - San Jose CA
Robert J. Lang - Pleasanton CA

Assignee:

SDL, Inc. - San Jose CA

International Classification:

H01S 300

US Classification:

3593413, 35934133

Abstract:

A pump source for rare earth and Raman amplifiers or for distributed amplification uses two or more light sources to generate two source beams that are combined by a beam combiner to form the output pump beam. In accordance with one embodiment, the light sources are a diode laser array having be two or more monolithic laser stripes providing dual output beams having substantially the same polarization, such as the TE mode. One of the polarized due outputs is rotated 90Â and both beams are applied to a birefringent crystal that combines the beams for insertion into an optical fiber or into a rare earth doped fiber or into a fiber capable of Raman amplification via SRS. The power output of each polarization in the combined beam can be measured and used to drive a feedback circuit that controls the current provided to each diode in order to maintain the power in the two polarization components of the output beam equal.

US Patent:

6411323, Jun 25, 2002

Filed:

Dec 7, 2000

Appl. No.:

09/732477

Inventors:

Robert G. Waarts - Fremont CA
David F. Welch - Menlo Park CA

Assignee:

SDL, Inc. - San Jose CA

International Classification:

B41J 2700

US Classification:

347241, 347256, 385 37

Abstract:

Power scaling by multiplexing multiple fiber gain sources with different wave-lengths is useful in printing applications requiring higher optical powers to perform the printing function, such as through thermal inducement in thermal ablation, thermal fusion, thermal diffusion or thermal transfer. A marking system is disclosed using a plurality of laser sources operating at different wavelengths with their respective outputs coupled into a respective single mode fiber. At least one WDM combiner is coupled to receive and combine the laser source outputs into a single output. The combined power single output provides sufficient power intensity to induce thermal marking on a marking medium.

US Patent:

6433306, Aug 13, 2002

Filed:

Jun 2, 2000

Appl. No.:

09/585262

Inventors:

Stephen G. Grubb - Fremont CA
David F. Welch - Menlo Park CA
Raymond Zanoni - Fremont CA

Assignee:

JDS Uniphase Corp. - San Jose CA

International Classification:

B23K 2606

US Classification:

21912173, 21912168, 21912165

Abstract:

A high power laser optical amplifier system for material processing comprises multiple stage fiber amplifiers with rejection of propagating ASE buildup in and between the amplifier stages as well as elimination of SBS noise providing output powers in the range of about 10 J to about 100 J or more. The system is driven with a time varying drive signal from a modulated semiconductor laser signal source to produce an optical output allowing modification of the material while controlling its thermal sensitivity by varying pulse shapes or pulse widths supplied at a desire repetition rate via modulation of a semiconductor laser signal source to the system to precisely control the applied power application of the beam relative to the thermal sensitivity of the material to be processed. The high power fiber amplifier system has particular utility in high power applications requiring process treatment of surfaces, such as polymeric, organic, ceramic and metal surfaces, e. g. , material processing, surface texturing, heat treatment, surface engraving, fine micro-machining, surface ablation, cutting, grooving, bump forming, coating, soldering, sealing, surface diffusion and surface conversion to a compound.