Steven N Patterson

US Patent:

6810067, Oct 26, 2004

Filed:

Sep 26, 2002

Appl. No.:

10/255443

Inventors:

Taha Masood - Plano TX
Steven Gregory Patterson - Plano TX
Gary A. Evans - Plano TX

Assignee:

Photodigm, Inc. - Richardson TX

International Classification:

H01S 308

US Classification:

372102, 372 43, 372 45, 372 46

Abstract:

A laser source is provided by the present invention, comprising a laser diode and has an active region with asymmetric distributed Bragg reflectors (DBRs) at either end to reflect light within the cavity, and an outcoupling grating in the center of the device, which couples light out of the cavity. One DBR is long and shallow, with a narrow-band reflective spectrum. The other DBR is short and deep, with a wide-band reflective spectrum. The lasing wavelength is determined by the reflective spectrum overlap of the two DBRs. Since the shallow DBR is highly reflective to only one Fabry Perot wavelength, and the deep DBR is highly reflective to a wide band of Fabry-Perot wavelengths, it is the reflective spectrum of the shallow DBR that determines the lasing wavelength.

US Patent:

6888874, May 3, 2005

Filed:

Jan 22, 2003

Appl. No.:

10/348920

Inventors:

Taha Masood - Plano TX, US
Steven Gregory Patterson - Plano TX, US
Gary A. Evans - Plano TX, US
Nuditha Vibhavie Amarasinghe - Richardson TX, US

Assignee:

Photodigm, Inc. - Richardson TX

International Classification:

H01S005/00
H01S003/08

US Classification:

372 96, 372 50

Abstract:

A laser diode system is provided. The laser comprises first and second reflective gratings at each end of the laser. The laser further comprises an outcoupling grating between the first and second reflective gratings, wherein the outcoupling grating couples light out of the laser. The reflectors and outcoupling grating each have a unique wide-band reflective spectrum. A first laser cavity exists between the first and second reflective gratings. A second laser cavity exists between the first reflective grating and the outcoupling grating. A third laser cavity exists between the second reflective grating and the outcoupling grating, and a fourth laser cavity exists with in the outcoupling region. The overlap of reflective spectra determine the lasing wavelengths that reach resonance within each cavity. Wavelengths resonant in one cavity are suppressed in the others unless a wavelength is resonant in all cavities.

US Patent:

7313158, Dec 25, 2007

Filed:

Feb 8, 2005

Appl. No.:

11/055128

Inventors:

Gary Alan Evans - Plano TX, US
Taha Masood - Plano TX, US
Steven Gregory Patterson - Plano TX, US
Nuditha Vibhavie Amarasinghe - Richardson TX, US
Jerome K. Butler - Richardson TX, US

Assignee:

Photodigm, Inc. - Richardson TX

International Classification:

H01S 5/00
H01S 3/13
H01S 3/08

US Classification:

372 50124, 372 29016, 372 29023, 372102

Abstract:

A single-mode grating-outcoupled surface emitting (GSE) semiconductor laser architecture is provided. This architecture enables high speed modulation of the GSE laser, which is accomplished by only varying the relative phase of counter propagating waves in the outcoupler grating region of the lasing cavity.

US Patent:

7313159, Dec 25, 2007

Filed:

Dec 23, 2004

Appl. No.:

11/021535

Inventors:

Nuditha Vibhavie Amarasinghe - Richardson TX, US
Taha Masood - Plano TX, US
Steven Gregory Patterson - Plano TX, US
Gary Alan Evans - Plano TX, US

Assignee:

Photodigm, Inc. - Richardson TX

International Classification:

H01S 3/08
H01S 5/00

US Classification:

372102, 372 501, 372 5011, 372 50124

Abstract:

An improved grating-outcoupled surface-emitting semiconductor laser architecture is provided. A second-order grating is placed between two distributed Bragg reflector gratings. The period of the second order grating is positively or negatively detuned from the distributed Bragg reflector selected optical wavelength at which the laser operates. Detuning of the second-order grating towards shorter or longer wavelengths allows kink-free, linear LI curves light output versus forward current) for grating-outcoupled surface-emitting lasers. Due to the detuning of the outcoupler grating, the outcoupled radiation emits two beams that deviate slightly from the normal axis. A design point may then be chosen where the power outcoupled by symmetric and antisymmetric modes cross and where the outcoupled power is independent of the phase variation.