K. Cooper

Bio: K. Cooper is an academic researcher. The author has contributed to research in topics: Schottky diode & IMPATT diode. The author has an hindex of 1, co-authored 1 publications receiving 4 citations.

High-power 11 GHz GaAs hi-lo Impatt diodes with titanium Schottky barriers

Abstract: Schottky-barrier hi-lo GaAs Impatt diodes with Ti-Pt-Au contacts have been fabricated for the 10.7?11.7 GHz band. At 180°C junction temperature rise the diodes have produced over 5 W of output power and up to 24% efficiency from an 11 GHz oscillator. Initial life tests show potential for high reliability.

Method of manufacturing heterojunction bipolar transistor

Abstract: A method of manufacturing a heterojunction bipolar transistor comprising the steps of forming a first semiconductor layer of a first conductivity type (108, 110) as a collector on a semiconductor substrate (112), forming a second semiconductor layer of a second conductivity type (106) as a base on the first semiconductor layer, forming a third semiconductor layer of the first conductivity type (100, 102, 104) as an emitter on the second semiconductor layer, the third and second semiconductor layers constituting a heterojunction, selectively forming a first mask on the third semiconductor layer, ion-implanting ions of an impurity of the second conductivity type Into the resultant structure using a first mask, thereby forming an external base region (118a) of the second conductivity type extending to the second semiconductor layer, forming a second mask on a side wall of the first mask, and ion-implanting a predetermined material into the resultant structure using the first and second masks, thereby forming a high-resistance layer (128) for isolating the external base region in self-alignment with the emitter.

Birefringence properties of twin-core fibers by finite differences

Abstract: A new type of optical fiber with a twin-core is proposed exhibiting good birefringence properties. The theoretical analysis of the structure is performed using a finite difference method based on a vector potential formulation. The birefringence of the twin-core fiber is compared to that of an elliptical step-index guide, showing the advantage of the former. It also appears that the normalized birefringence parameter currently used for the elliptical fiber does not apply in the monomode region.

Polarization-maintaining single-mode fibers

Abstract: Polarization-maintaining single-mode fibers will find application in acoustooptic sensors and fiber gyroscopes. In this study both stress-induced birefringence and elliptical core polarization-maintaining single-mode fibers were developed and evaluated. The two fiber types were compared in terms of core dimension, numerical aperture, attenuation, and beat length, a measure of the polarization maintenance. For comparative beat length values the stress-induced birefringence fibers had lower attenuation and larger core diameter than the elliptical core fibers.