Bridgelux Incorporated

Jds Uniphase Corporation

University of California

Kabushiki Kaisha Toshiba

Agilent Technologies, Inc.

Toshiba Techno Center Inc.

Syn-Yem Hu

Steven D Lester

Ghulam Hasnain

Larry Allen Coldren

Zhong Pan

Jeff Ramer

Tchang-Hun Oh

I-Hsing Tan

A light source and method for making the same are disclosed. The light source includes a plurality of Segmented LEDs connected in parallel to a power bus and a controller. The power bus accepts a variable number of Segmented LEDs. The controller receives AC power and provides a power signal on the power bus. Each Segmented LED is characterized by a driving voltage that is greater than 3 times the driving voltage of a conventional LED fabricated in the same material system as the Segmented LED. The number of Segmented LEDs in the light source is chosen to compensate for variations in the light output of individual Segmented LEDs introduced by the manufacturing process. In another aspect of the invention, the number of Segmented LEDs connected to the power bus can be altered after the light source is assembled.

Light sources utilizing segmented LEDs to compensate for manufacturing variations in the light output of individual segmented LEDs

A light emitting diode (LED) assembly may include an LED semiconductor attached to a first surface of a submount made of optically transparent material. The submount may redirect back side light emitted by the LED semiconductor light away from the LED semiconductor to increase recovery of back side light. The submount may be used with an external bulk reflecting element. The submount may itself include a reflective coating at a second surface opposite from the first surface and be mounted on a reflecting substrate. The submount may include a phosphor forming the first surface or the second surface. The first surface or the second surface may be a textured surface. An array of LED semiconductors may be mounted to the submount. The array of LED semiconductors may be disposed on the submount in an arrangement that optimizes total light output of the LED assembly.

Submount for LED device package

Gold is used as a micromask to roughen a gallium nitride (GaN) surface in an LED device. In one example, a mesh of ITO (Indium Tin Oxide) is formed on a GaN layer. The mesh has holes that extend down to the GaN. A layer of silicon dioxide is deposited so that it covers the GaN at the bottoms of the holes. A layer of gold is formed over the oxide. A thermal treatment causes the gold to ball up into small gold features. These gold features are used as a micromask in a subsequent etching step. Areas of the bottoms of the holes that are not covered by a gold feature are etched. Etching occurs through the oxide and down into the GaN. The roughening process involves no silver, and involves no harsh cleaning solvents or processes that might otherwise have been used were the micromask made of silver.

Gold micromask for roughening to promote light extraction in an LED

A light source and method for making the same are disclosed. The light source includes a substrate and a light emitting structure that is deposited on the substrate. A barrier divides the light emitting structure into first and second segments that are electrically isolated from one another. A serial connection electrode connects the first segment in series with the second segment. A first blocking diode between the light emitting structure and the substrate prevents current from flowing between the light emitting structure and the substrate when the light emitting structure is emitting light. The barrier extends through the light emitting structure into the first blocking diode.

Light sources with serially connected LED segments including current blocking diodes

The present invention relates to a stable mesa-type photodetector with lateral diffusion junctions. The invention has found that without resorting to the complicated regrowth approach, a simple Zn diffusion process can be used to create high-quality semiconductor junction interfaces at the exposed critical surface or to terminate the narrow-bandgap photon absorption layers. The invention converts the epi material layers near or at the vicinity of the etched mesa trench or etched mesa steps into a different dopant type through impurity diffusion process. Preferably the diffused surfaces are treated with a subsequent surface passivation. This invention can be applied to both top-illuminating and bottom-illuminating configurations.

Mesa-type photodetectors with lateral diffusion junctions

The present invention provides a highly reliable photodiode, as well as a simple method of fabricating such a photodiode. During fabrication of the photodiode, a grading layer is epitaxially grown on a top surface of an absorption layer, and a blocking layer, for inhibiting current flow, is epitaxially grown on a top surface of the grading layer. The blocking layer is then etched to expose a window region of the top surface of the grading layer. Thus, the etched blocking layer defines an active region of the absorption layer. A window layer is epitaxially regrown on a top surface of the blocking layer and on the window region of the top surface of the grading layer, and is then etched to form a window mesa.

Photodiode and method of fabrication

A method of manufacture of an avalanche photodiode involving a step of making a recess in a top window layer of an avalanche photodiode layer stack, such that a wall surrounding the recess runs smoothly and gradually from the level of the recess to the level of the window layer. Further, diffusing a dopant over the entire window layer area so as to form a p-n junction at the bottom of the recess, and providing a first electrical isolation region around the recess by buried ion implantation or wet oxidation in order to limit the flow of electrical current to the p-n junction. Forming an isolation trench around the photodiode and a second electrical isolation region by ion implantation into the trench such that the second electrical isolation region runs through the absorption layer of the photodiode.

Semiconductor photodiode and method of manufacture thereof

A vertical cavity surface emitting laser (VCSEL) has a top mirror structure with a surface, a light generation region, and a bottom mirror structure for reflecting light toward said top mirror structure. The VCSEL has a semiconductor portion with a surface that is disposed substantially planar with respect to the surface of the top mirror structure. At least one aperture-defining layer having an isolatable material is disposed in at least one of the bottom mirror structure and the top mirror structure. The aperture-defining layer has a conducting region, an insulating region having an aperture-defining surface for defining the conducting region, and a single trench adjacent to the insulating region for use in generating the insulating region. The trench having a continuous geometry for reducing the parasitic capacitance of the VCSEL.

High speed VCSEL

A low cost, high speed WDM optical link which employs a circular array of VCSEL emitters directly coupled to a multi-mode fiber through which multiple simultaneously optical transmissions are sent to an optical detector comprising a circular array of RCPD detectors receiving the multiple simultaneous transmissions. The emitters and detectors within each array are fabricated with a double-absorber design which avoids position sensitivity related to the cavity standing wave and eliminates the need for in-situ cavity-mode adjustment. In addition, a coupled-cavity structure is presented to achieve passbands with flat tops and steep sides to approach the ideal square-shape photoresponse and to ensure proper channel alignment.

Growing community of inventors

San Jose, CA, United States of America

Syn-Yem Hu