Geoffrey R Taylor

US Patent:

53291379, Jul 12, 1994

Filed:

May 21, 1993

Appl. No.:

8/066322

Inventors:

Geoffrey W. Taylor - Holmdel NJ
Tim Vang - Belmar NJ

Assignee:

The United States of America as represented by the Secretary of the Air
Force - Washington DC

International Classification:

H01L 2714
H01L 3100

US Classification:

257 21

Abstract:

An optical switch comprises a heterojunction transistor having a source electrode, a gate, a mesa, and three self-aligned waveguides, the mesa being ion implanted and having a single quantum well under the gate electrode, the single quantum well being comprises of undoped, narrow bandgap material bound on both sides by regions p-doped, wide bandgap material, both of said p-doped regions have symmetrically graded bandgaps, being most narrow next to the quantum well and increasing out to a wide and constant value away from the quantum well. A highly n-doped and totally depleted charge sheet is placed in a wide bandgap material, very near the gate side of the quantum well heterojunction. The charge sheet serves to induce a voltage controllable inversion channel within the quantum well. A source of optical energy is applied to one of said waveguides, and a total internal reflection is created in the switch by inducing a change in refractive index under the gate by means of a charge applied from the source electrode.

US Patent:

50103741, Apr 23, 1991

Filed:

Jun 5, 1990

Appl. No.:

7/533549

Inventors:

Paul W. Cooke - Fair Haven NJ
Geoffrey W. Taylor - Holmdel NJ

Assignee:

AT&T Bell Laboratories - Murray Hill NJ

International Classification:

H01L 29161
H01L 3300
H01S 319

US Classification:

357 16

Abstract:

A quantum well laser exhibiting near ideal switching characteristics, high power conversion efficiency and, moreover, capable of utilizing the advantageous characteristics of a double heterostructure optoelectronic switch comprises a quantum well region disposed between carrier confinement regions. In particular, the interface between the qunatum well regioin and a confinement region is adapted to the formation of an inversion layer.

US Patent:

51112558, May 5, 1992

Filed:

Jun 5, 1990

Appl. No.:

7/533636

Inventors:

Philip A. Kiely - Tinton Falls NJ
Geoffrey W. Taylor - Holmdel NJ

Assignee:

AT&T Bell Laboratories - Murray Hill NJ

International Classification:

H01L 2980

US Classification:

357 22

Abstract:

A high transconductance field effect transistor is realized by controlling the doping level in a conducting channel buried beneath a heterointerface. In one exemplary embodiment, a channel comprising an undoped, high mobility, narrow band gap quantum well in combination with an intermediate band gap layer is formed beneath a heterointerface. The heterojunction interface is between a wide band gap layer and the quantum well region. A charge sheet having the same conductivity type as the wide bandgap layer is formed near the heterointerface. Advantageously, the transconductance is enhanced by conduction in the undoped filled quantum well region.

US Patent:

52241157, Jun 29, 1993

Filed:

Jul 17, 1991

Appl. No.:

7/731688

Inventors:

Geoffrey W. Taylor - Holmdel NJ
Daniel P. Doctor - Morganville NJ

Assignee:

The United States of America as represented by the Secretary of the Air
Force - Washington DC

International Classification:

H01S 319

US Classification:

372 50

Abstract:

A distributed feedback (DFB) laser for use in a bipolar field effect transistor laser (known as a BICFET laser) produces a single mode, stable, tunable laser. The single mode, stable, tunable characteristics of the laser are achieved by modifying the structure and operation of a previously disclosed high speed integrated heterojunction field-effect transistor laser by the inclusion of a grating in the n+ active regions to create a periodic refractive index profile. Independent operation of two n+ quantum wells provides frequency tuning through simultaneous and independent control of the mode spacing or mode frequency and the distributed feedback frequency.

US Patent:

48069973, Feb 21, 1989

Filed:

Jan 22, 1988

Appl. No.:

7/147052

Inventors:

John G. Simmons - St. Annes-On-Sea, GB2
Geoffrey W. Taylor - Berkeley Heights NJ

International Classification:

H01L 29161

US Classification:

357 16

Abstract:

A double heterostructure opto-electronic device capable of both electronic and photonic switching is described.

US Patent:

53291131, Jul 12, 1994

Filed:

Jun 10, 1993

Appl. No.:

8/075087

Inventors:

Geoffrey W. Taylor - Holmdel NJ
Timothy A. Vang - Tinton Falls NJ

Assignee:

AT&T Bell Laboratories - Murray Hill NJ

International Classification:

H01J 4014

US Classification:

250214LS

Abstract:

An optoelectronic switching node is disclosed wherein two input optical beams can be switched in the sense that they can be regenerated in either one of two output spatial locations in response to input control signals. Each one of the input optical beams is coupled to a resonant cavity detector which generates a current when its corresponding optical beam impinges on its resonant cavity. Output optical beams are regenerated by two inversion channel lasers each one of which has emitter, source and sub-collector terminals and is bistable in the sense that it can be switched on and off by currents delivered into and taken out of its source terminal. Heterojunction field effect transistors are used to selectively couple the currents generated by the resonant cavity detectors to the source terminals of the lasers in order to turn them on. Two heterojunction field effect transistors are each connected as a two terminal impedance between the source terminal of each laser and a reference potential in order to turn the laser off when no current is being provided by a detector. Two additional heterojunction field effect transistors are also connected as two terminal load impedances for each of the lasers.

US Patent:

53671775, Nov 22, 1994

Filed:

May 28, 1993

Appl. No.:

8/070649

Inventors:

Geoffrey W. Taylor - Holmdel NJ
Steve Sargood - Holmdel NJ

Assignee:

The United States of America as represented by the Secretary of the Air
Force - Washington DC

International Classification:

H01L 2714
H01L 3100

US Classification:

257 20

Abstract:

An optical device which uses a heterojunction field effect detector (HFED) having wavelength selectivity through the use of ion-implantation, and a wavelength selective grating. The device incorporates a Grinsch layer structure with a single GaAs quantum well. The optical power from the lens couples into a guided mode. The absorbing region is the quantum well itself. In the operation of the HFED, a positive bias is applied to the gate, and the depleted GaAs quantum well below the gate absorbs the photons, generating electron-hole pairs. The photocarriers are separated by the electric field before recombination can occur. The photocurrent is then produced in the external circuit by appropriately biasing the device. For collecting the electrons, a positive bias is applied to both the source and drain contacts, which act as dual drain contacts. The holes are removed via the collector which is maintained at ground.