University of California

Jay A Skidmore

Barry L Freitas

Stephen Anthony Payne

Larry Allen Coldren

Mark A Emanuel

John P Wooldridge

A microchannel-cooled, optically corrected, laser diode array is fabricated by mounting laser diode bars onto Si surfaces. This approach allows for the highest thermal impedance, in a ruggedized, low-cost assembly that includes passive microlens attachment without the need for lens frames. The microlensed laser diode array is usable in all solid-state laser systems that require efficient, directional, narrow bandwidth, high optical power density pump sources.

Ruggedized microchannel-cooled laser diode array with self-aligned microlens

A monolithic, electrically-insulating substrate that contains a series of notched grooves is fabricated. The substrate is then metalized so that only the top surface and one wall adjacent to the notch are metalized. Within the grooves is located a laser bar, an electrically-conductive ribbon or contact bar and an elastomer which secures/registers the laser bar and ribbon (or contact bar) firmly along the wall of the groove that is adjacent to the notch. The invention includes several embodiments for providing electrical contact to the corresponding top surface of the adjacent wall. In one embodiment, after the bar is located in the proper position, the electrically conductive ribbon is bent so that it makes electrical contact with the adjoining metalized top side of the heatsink.

Monolithic laser diode array with one metalized sidewall

Monolithic microlens frames enable the fabrication of monolithic laser diode arrays and are manufactured inexpensively with high registration, and with inherent focal length compensation for any lens diameter variation. A monolithic substrate is used to fabricate a low-cost microlens array. The substrate is wet-etched or sawed with a series of v-grooves. The v-grooves can be created by wet-etching, by exploiting the large etch-rate selectivity of different crystal planes. The v-grooves provide a support frame for either cylindrical or custom-shaped microlenses. Because the microlens frames are formed by photolithographic semiconductor batch-processing techniques, they can be formed inexpensively over large areas with precise lateral and vertical registration. The v-groove has an important advantage for preserving the correct focus for lenses of varying diameter.

Microlens frames for laser diode arrays

A substrate is used to fabricate a low-cost laser diode array. A substrate is machined from an electrically insulative material that is thermally conductive, or two substrates can be bonded together in which the top substrate is electrically as well as thermally conductive. The substrate thickness is slightly longer than the cavity length, and the width of the groove is wide enough to contain a bar and spring (which secures the laser bar firmly along one face of the groove). The spring also provides electrical continuity from the backside of the bar to the adjacent metalization layer on the laser bar substrate. Arrays containing one or more bars can be formed by creating many grooves at various spacings. Along the groove, many bars can be adjoined at the edges to provide parallel electrical conduction. This architecture allows precise and predictable registration of an array of laser bars to a self-aligned microlens array at low cost.

Low-cost laser diode array

Anisotropic chemically enhanced etching apparatus producing extremely low surface damage during the etching process. There is an evacuated main chamber in which an etching process takes place. A temperature-controlled, tiltable stage receives and holds the substrate to be etched within the main chamber. There is a nozzle directing a flow against a substrate mounted on the stage. There is a microwave cracker connected to a supply of molecular chlorine on an input side and connected to the nozzle on an output side for exciting and disassociating the molecular chlorine to be discharged through the nozzle as chlorine radicals. A first controller is operably connected to the cracker for controlling the flow of chlorine radicals being emitted from the nozzle. There is an ion gun for controlling the beam of ions. The second controller includes a feedback signal.

Growing community of inventors

Livermore, CA, United States of America

Jay A Skidmore