Hughes Aircraft Company

Mark Lui

Mehran Matloubian

Ross A McFarlane

William E Stanchina

Takyiu Liu

Loi D Nguyen

Robert A Metzger

Linda M Jelloian

April S Brown

Joseph A Henige

A wide-bandwidth variable attenuator/modulator incorporating a region of material comprising a combination of a ferromagnetic/nonmagnetic material which exhibits a Giant Magnetoresistance (GMR) effect.

Wide-bandwidth variable attenuator/modulator using giant magnetoristance

High breakdown voltages for AlInAs layers in InP-based devices, such as a gate layer in an InP HEMT or a collector layer in a heterojunction bipolar transistor, are achieved by growing the AlInAs layer by MBE at a substrate temperature about 70.degree.-125.degree. C. below the temperature at which a 2.times.4 reflective high energy diffraction pattern is observed. This corresponds to a growth temperature range of about 415.degree.-470.degree. C. for a 540.degree. 2.times.4 reconstruction temperature. Preferred growth temperatures within these ranges are 80.degree. C. below the 2.times.4 reconstruction temperature, or about 460.degree. C. Higher breakdown voltages are obtained than when the AlInAs layer is grown at either higher or lower temperatures.

Method of growing high breakdown voltage allnas layers in InP devices by

A radiation wavelength conversion device is implemented in the form of a waveguide that includes a single crystal halide-based cladding layer, and a halide-based active layer. The active layer has a greater refractive index than the cladding layer, is approximately lattice matched with the cladding layer, and includes a dopant that causes it to respond to input radiation at one wavelength by emitting radiation at a different wavelength. The active layer can either form part of a laser resonator cavity, or can operate through spontaneous emission. It is preferably about 3.5-5 microns thick to induce single-mode propagation, and can be divided into separate waveguiding channels to limit beam fanning. The device is operable at room temperature, and can be fabricated using conventional microelectronics techniques.

Wavelength conversion waveguide

A donor layer (17) including an undoped wide bandgap material (14) and an n-type dopant (16) is deposited on a substrate (12) by molecular beam epitaxy (MBE) at a first temperature which is high enough for optimal growth of the donor layer (17). The dopant (16) is silicon or another material which exhibits surface segregation in the wide bandgap material (14) at the first temperature. An undoped spacer layer (18) of the wide bandgap material is deposited on the donor layer (17) at a second temperature which is sufficiently lower than the first temperature that surface segregation of the dopant material from the donor layer (17) into the spacer layer (18) is substantially suppressed. A channel layer (20) of a narrow bandgap material is formed on the spacer layer (18) at a third temperature which is higher than the second temperature and selected for optimal growth of the channel layer (20). The spacer layer (18) is substantially undoped, and the low temperature growth and reduction of donor movement reduces ionized impurity scattering in the channel layer (20).

Method of fabricating inverted modulation-doped heterostructure

Wavelength conversion waveguide and fabrication method

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Thousand Oaks, CA, United States of America

Mark Lui