Frederick D Johnson

US Patent:

6407407, Jun 18, 2002

Filed:

May 2, 2000

Appl. No.:

09/563314

Inventors:

Frederick G. Johnson - Lanham MD
Bikash Koley - College Park MD
Linda M. Wasiczko - College Park MD

Assignee:

The United States of America as represented by the Director of the National Security Agency - Washington DC

International Classification:

H01L 2906

US Classification:

257 18, 257 14, 438 39

Abstract:

A ridge laser that includes a Group III-V semiconductor material substrate; a first selectively oxidized at least one strain-compensated superlattice of Group III-V semiconductor material; a multiple quantum well active region; a second selectively oxidized at least one strain-compensated superlattice of Group III-V semiconductor material; a Group III-V semiconductor material cap layer; and a contact material. Each at least one strain-compensated superlattice includes at least two monolayers of a Group III-V semiconductor material and at least two monolayers of an aluminum-bearing Group III-V semiconductor material. In the preferred embodiment, the substrate is InP of any type; each selectively oxidized at least one strain-compensated superlattice of Group III-V semiconductor material is InAs/AlAs, where each at least one superlattice of InAs/AlAs includes at least two monolayers of InAs and at least two monolayers of AlAs; the multiple quantum well active region is InGaAsP lattice matched to the InP substrate, the Group III-V semiconductor material cap layer is InP, and the contact material is gold.

US Patent:

6493366, Dec 10, 2002

Filed:

May 2, 2000

Appl. No.:

09/564371

Inventors:

Frederick G. Johnson - Lanham MD
Bikash Koley - College Park MD
Linda M. Wasiczko - College Park MD

Assignee:

The United States of America as represented by the National Security Agency - Washington DC

International Classification:

H01S 500

US Classification:

372 45, 372 96, 372102

Abstract:

A vertical cavity surface emitting laser that includes a Group III-V semiconductor material substrate; a first Distributed Bragg Reflector mirror, where the first Distributed Bragg Reflector mirror includes at least seven pairs of layers, where each layer has a different index of refraction, where one of the layers is a Group III-V semiconductor material, and where the other layer is a completely oxidized at least one strain-compensated superlattice of Group III-V semiconductor material, where each at least one strain-compensated superlattice includes at least two monolayers of a Group III-V semiconductor material and at least two monolayers of an aluminum-bearing Group III-V semiconductor material; a first Group III-V semiconductor material layer; a first contact; a selectively oxidized at least one strain-compensated superlattice of Group III-V semiconductor material, where each at least one strain-compensated superlattice of Group III-V semiconductor material includes at least two monolayers of a Group III-V semiconductor material and at least two monolayers of an aluminum-bearing Group III-V semiconductor material; a second Group III-V semiconductor material layer; a second contact; and a second Distributed Bragg Reflector mirror that is identical to the first Distributed Bragg Reflector mirror.

US Patent:

6531414, Mar 11, 2003

Filed:

May 2, 2000

Appl. No.:

09/563457

Inventors:

Frederick G. Johnson - Lanham MD
Bikash Koley - College Park MD
Linda M. Wasiczko - College Park MD

Assignee:

The United States of America as represented by The National Security Agency - Washington DC

International Classification:

H01L 2131

US Classification:

438785, 438767, 438125, 257 9, 257 15

Abstract:

A method of forming a native oxide from at least one strain-compensated superlattice of Group III-V semiconductor material, where each at least one superlattice includes two monolayers of a Group III-V semiconductor material and at least two monolayers of an aluminum-bearing Group III-V semiconductor material. The method entails exposing each at least one superlattice to a water-containing environment and a temperature of at least about 425 degrees Celsius to convert at least a portion of said superlattice to a native oxide. The native oxide thus formed is useful in electrical and optoelectrical devices, such as lasers.

US Patent:

6614977, Sep 2, 2003

Filed:

Sep 4, 2001

Appl. No.:

09/944207

Inventors:

Frederick G. Johnson - Lanham MD
Oliver S. King - Annapolis MD
John V. Hryniewicz - Columbia MD
Lance G. Joneckis - Severna Park MD
Sai T. Chu - Greenbelt MD
David M. Gill - Pasadena MD

Assignee:

Little Optics, Inc. - Annapolis Junction MD

International Classification:

G02B 610

US Classification:

385129, 385130, 385131, 385141

Abstract:

Devices and methods for the vapor deposition of amorphous, silicon-containing thin films using vapors comprised of deuterated species. Thin films grown on a substrate wafer by this method contain deuterium but little to no hydrogen. Optical devices comprised of optical waveguides formed using this method have significantly reduced optical absorption or loss in the near-infrared optical spectrum commonly used for optical communications, compared to the loss in waveguides formed in thin films grown using conventional vapor deposition techniques with hydrogen containing precursors. In one variation, the optical devices are formed on a silicon-oxide layer that is formed on a substrate, such as a silicon substrate. The optical devices of some variations are of the chemical species SiO N :D. Since the method of formation requires no annealing, the thin films can be grown on electronic and optical devices or portions thereof without damaging those devices.

US Patent:

6768828, Jul 27, 2004

Filed:

May 20, 2003

Appl. No.:

10/441052

Inventors:

David M. Gill - Annapolis Junction MD
Oliver S. King - Annapolis Junction MD
Frederick G. Johnson - Annapolis Junction MD

Assignee:

Little Optics Inc. - Annapolis Junction MD

International Classification:

G02B 636

US Classification:

385 14, 385129, 385130, 385131, 385132

Abstract:

The integrated optical circuit of the present invention includes a substrate with a first cladding layer. A first core layer having one or more waveguiding elements is formed on the first cladding layer. A second cladding layer surrounds the waveguiding elements of the first core layer; the refractive index of the first and second cladding layers are selected to be less than the refractive index of the waveguiding element(s). Through simultaneous cladding material deposition and cladding material removal, the second cladding layer as deposited is substantially self-planarized, enabling further layers to be positioned on the second cladding layer without necessitating intermediate planarization. Further, the present invention permits planar waveguide cores having submicron core spacings to be covered by a subsequently-deposited cladding layer without cladding gaps, seams or other deleterious cladding defects.

US Patent:

6771868, Aug 3, 2004

Filed:

Jun 20, 2003

Appl. No.:

10/465881

Inventors:

Frederick G. Johnson - Lanham MD
Oliver S. King - Annapolis MD
John V. Hryniewicz - Columbia MD
Lance G. Joneckis - Severna Park MD
Sai T. Chu - Greenbelt MD
David M. Gill - Pasadena MD

Assignee:

Little Optics, Inc. - Annapolis Junction MD

International Classification:

G02B 610

US Classification:

385129, 385130, 385131, 385141

Abstract:

Devices and methods for the vapor deposition of amorphous, silicon-containing thin films using vapors comprised of deuterated species. Thin films grown on a substrate wafer by this method contain deuterium but little to no hydrogen. Optical devices comprised of optical waveguides formed using this method have significantly reduced optical absorption or loss in the near-infrared optical spectrum commonly used for optical communications, compared to the loss in waveguides formed in thin films grown using conventional vapor deposition techniques with hydrogen containing precursors. In one variation, the optical devices are formed on a silicon-oxide layer that is formed on a substrate, such as a silicon substrate. The optical devices of some variations are of the chemical species SiO N :D. Since the method of formation requires no annealing, the thin films can be grown on electronic and optical devices or portions thereof without damaging those devices.

US Patent:

7043133, May 9, 2006

Filed:

Jun 10, 2004

Appl. No.:

10/864511

Inventors:

Frederick G. Johnson - Lanham MD, US
Oliver S. King - Annapolis MD, US
David M. Gill - Pasadena MD, US
Timothy J. Davidson - Baltimore MD, US
Warren P. Berk - Joppatowne MD, US

Assignee:

Little Optics, Inc. - Annapolis Junction MD

International Classification:

G02B 6/00
G02B 6/10
C03B 37/23
C03B 37/22

US Classification:

385142, 385129, 385130, 385131, 385141, 65385, 65386

Abstract:

Silicon-oxycarbide optical waveguides and thermooptic devices include a substrate and a first cladding layer having a first refractive index positioned over a substrate. A first core layer comprising silicon, oxygen, and carbon and having a core refractive index is formed on the first cladding layer by chemical vapor deposition using at least two precursors: one inorganic silicon precursor gas and at least one second precursor gas comprising carbon and oxygen. Alternatively, at least three precursors can be used: one inorganic silicon precursor gas, a second precursor comprising carbon, and a third precursor comprising oxygen. The core layer is lithographically patterned to define waveguide elements. A second cladding layer having a second cladding refractive index is formed to surround the optical core waveguiding element of the first core layer.

US Patent:

7231113, Jun 12, 2007

Filed:

Aug 19, 2005

Appl. No.:

11/208338

Inventors:

Sai Chu - Columbia MD, US
Frederick G. Johnson - Ellicott City MD, US
Oliver King - Annapolis MD, US
Marcus Schuetz - Sevem MD, US
Brent Little - Columbia MD, US

Assignee:

Infinera Corporation - Sunnyvale CA

International Classification:

G02B 6/02
G02F 1/295

US Classification:

385 30, 385 8, 385 16

Abstract:

An integrated optical device is disclosed comprising a substrate, optical waveguide, and compound optical resonator having a temperature sensor, at least two coupled optical resonators, and a heater localized to each optical resonator. An optical input signal is coupled to one of the resonators making up the compound resonator to form an optical output signal. The center wavelength and shape of the output signal is optimized with a feedback loop using the temperature sensor to control the power dissipated in at least one of the localized heaters. The power dissipated in the remaining resonator heaters is set according to a predetermined function having as an input variable the power dissipated in the resonant heater under control of the said feedback loop.