University of Illinois

Other

James J Coleman

Victor C Elarde

Mark S Zediker

S David Roh

Paul Vannest Braun

Karl Hess

Reuel Bennett Swint

Varun B Verma

Mark A Emanuel

Ted K Higman

Erik C Nelson

A semiconductor laser that includes an active region, claddings and electrical contacts to stimulate emissions from the active region, where a coupled waveguide guides emission. The waveguide includes a broad area straight coupling region that fans out into an array of narrower Individual curved coupled waveguides at an output facet of the laser. The individual curved coupled waveguides are curved according to Lorentzian functions that define the waveguide curvature as a function of position along the device. The integral length of each individual curved coupled waveguide differs from adjacent individual curved coupled waveguides by an odd number of half-wavelengths. The coupled waveguide array shapes the optical field output of the semiconductor laser such that a large fraction of the power is emitted into a small angular distribution using interference phenomena. A laser of the invention produces high power output with a very high quality, narrow beam shape.

Curved coupled waveguide array and laser

The invention provides a quantum well active region for an optoelectronic device. The quantum well active region includes barrier layers of high bandgap material. A quantum well of low bandgap material is between the barrier layers. Three-dimensional high bandgap barriers are in the quantum well. A preferred semiconductor laser of the invention includes a quantum well active region of the invention. Cladding layers are around the quantum well active region, as well as a waveguide structure.

Quantum well active region with three dimensional barriers and fabrication

A porous device for optical and electronic applications comprises a single crystal substrate and a porous single crystal structure epitaxially disposed on the substrate, where the porous single crystal structure includes a three-dimensional arrangement of pores. The three-dimensional arrangement may also be a periodic arrangement. A method of fabricating such a device includes forming a scaffold comprising interconnected elements on a single crystal substrate, where the interconnected elements are separated by voids. A first material is grown epitaxially on the substrate and into the voids. The scaffold is then removed to obtain a porous single crystal structure epitaxially disposed on the substrate, where the single crystal structure comprises the first material and includes pores defined by the interconnected elements of the scaffold.

Porous device for optical and electronic applications and method of fabricating the porous device

Dual-wavelength operation is easily achieved by biasing the gain section. Multiple gratings spaced apart from each other are separated from an output aperture by a gain section. A relatively low coupling coefficient, &#x3ba;, in the front grating reduces the added cavity loss for the back grating mode. Therefore, the back grating mode reaches threshold easily. The space section lowers the current induced thermal interaction between the two uniform grating sections, significantly reducing the inadvertent wavelength drift. As a result, a tunable mode pair separations (&#x394;&#x3bb;) as small as 0.3 nm and as large as 6.9 nm can be achieved.

Current biased dual DBR grating semiconductor laser

A laser heterostructure having an active layer, a lateral waveguide terminating in an output aperture, and a gain section with a current drive electrode. A rear surface distributed Bragg grating with a tuning current electrode is formed on a surface of said laser heterostructure. The laser also includes a front surface distributed Bragg grating with a tuning current electrode on a surface of the laser heterostructure. The front surface distributed Bragg grating is closer to the output aperture than the rear surface distributed Bragg grating, There is a space between the rear surface distributed Bragg grating and the front surface distributed Bragg grating. A current drive electrode is formed on the space. Operation is best when the front surface distributed Bragg grating has adequate reflectivity at the Bragg wavelength with minimal scattering loss at other wavelengths, particularly at the wavelength of the rear surface Bragg grating.

A semiconductor quantum well laser having separate lateral confinement of injected carriers and the optical mode. A ridge waveguide is used to confine the optical mode. A buried heterostructure confines injected carriers. A preferred embodiment laser of the invention is a layered semiconductor structure including optical confinement layers. A buried heterojunction quantum well within the optical confinement layers is dimensioned and arranged to confine injected carriers during laser operation. A ridge waveguide outside the optical confinement layers is dimensioned and arranged with respect to the buried heterojunction to confine an optical mode during laser operation. An index step created by the buried heterojunction is substantially removed from the optical mode.

Separate lateral confinement quantum well laser

A semiconductor laser structure based upon a rib waveguide geometry which includes a uniform region and a flared and tapered region. The uniform region has a generally constant thickness and width. The flared tapered region gradually increases in width and decreases in thickness from the uniform region to a wide end. Fabrication is by selective area epitaxy with dielectric stripes in a dual stripe dielectric mask used to defined the two dimensional varying flare in the waveguide changing in thickness as a function of the flare width.

Flared and tapered rib waveguide semiconductor laser and method for making same

A semiconductor heterostructure device is disclosed which includes a first semiconductor layer having a barrier layer disposed thereon, the barrier layer being formed of a semiconductor material having a wider bandgap than the material of the first semiconductor layer. A carrier transport layer is disposed on the barrier layer, the carrier transport layer being formed of a semiconductor material having a narrower bandgap than the material of the barrier layer. A contact layer is disposed on the carrier transport layer. A negative potential is applied to the contact layer with respect to the first semiconductor layer. In operation, for small voltages, under the indicated bias configuration, electrons supplied to the carrier transport layer by the source of negative potential supply will be blocked at the barrier presented by the larger bandgap barrier layer, and little current will flow. As the bias voltage is increased, these blocked electrons are under the influence of

Growing community of inventors

Monticello, IL, United States of America

James J Coleman