David A Craft

US Patent:

53496019, Sep 20, 1994

Filed:

Sep 20, 1993

Appl. No.:

8/123835

Inventors:

John P. Hohimer - Albuquerque NM
David C. Craft - Albuquerque NM

Assignee:

The United States of America as represented by the United States
Department of Energy - Washington DC

International Classification:

H01S 3083

US Classification:

372 94

Abstract:

Unidirectional ring lasers formed by integrating nonreciprocal optical elements into the resonant ring cavity. These optical elements either attenuate light traveling in a nonpreferred direction or amplify light traveling in a preferred direction. In one preferred embodiment the resonant cavity takes the form of a circle with an S-shaped crossover waveguide connected to two points on the interior of the cavity such that light traveling in a nonpreferred direction is diverted from the cavity into the crossover waveguide and reinjected out of the other end of the crossover waveguide into the cavity as light traveling in the preferred direction.

US Patent:

53982568, Mar 14, 1995

Filed:

May 10, 1993

Appl. No.:

8/061400

Inventors:

John P. Hohimer - Albuquerque NM
David C. Craft - Albuquerque NM

Assignee:

The United States of America as represented by the United States
Department of Energy - Washington DC

International Classification:

H01S 3083

US Classification:

372 94

Abstract:

Two ring diode lasers are optically coupled together to produce tunable, stable output through a Y-junction output coupler which may also be a laser diode or can be an active waveguide. These devices demonstrate a sharp peak in light output with an excellent side-mode-rejection ratio. The rings can also be made of passive or active waveguide material. With additional rings the device is a tunable optical multiplexer/demultiplexer.

US Patent:

56843089, Nov 4, 1997

Filed:

Feb 15, 1996

Appl. No.:

8/601904

Inventors:

Michael L. Lovejoy - Albuquerque NM
Benny H. Rose - Albuquerque NM
David C. Craft - Albuquerque NM
Paul M. Enquist - Cary NC
David B. Slater - Raleigh NC

Assignee:

Sandia Corporation - Albuquerque NM

International Classification:

H01L 310232

US Classification:

257184

Abstract:

A digital photoreceiver is formed monolithically on an InP semiconductor substrate and comprises a p-i-n photodetector formed from a plurality of InP/InGaAs layers deposited by an epitaxial growth process and an adjacent heterojunction bipolar transistor (HBT) amplifier formed from the same InP/InGaAs layers. The photoreceiver amplifier operates in a large-signal mode to convert a detected photocurrent signal into an amplified output capable of directly driving integrated circuits such as CMOS. In combination with an optical transmitter, the photoreceiver may be used to establish a short-range channel of digital optical communications between integrated circuits with applications to multi-chip modules (MCMs). The photoreceiver may also be used with fiber optic coupling for establishing longer-range digital communications (i. e. optical interconnects) between distributed computers or the like.