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Sophisticated packaging architectures have been developed that enable low cost, very high average power, long lived pumping of solid state lasers. Single water cooled manifolds now provide slab pumping of up to 2.5 kW of average optical power, while low cost yet flexible bar mounting techniques allow burn-in that enables very long lifetimes. Architecture modification allows for high peak power of up to 80 kW per water cooled pump manifold. Specialized high brightness packaging now allows approximately 20 watt cw bars to be lensed into less than 200 micrometers diameter spot sizes (approximately 54 kW/cm 2 ).

The reliability of high power continuous-wave (CW) 1 cm monolithic AlGaAs (808 nm) laser diodes is extensively investigated. Lasers with two total aperture sizes, 1800 micrometers and 3000 micrometers , are life tested at power levels of 10 W and 20 W, respectively for 1500 hours to 4000 hours at 30 degree(s)C heatsink temperature. These lasers exhibit no failures during the lifetests (total device hours of 45,000 hours for the 10 W lasers and 42,000 hours for the 20 W lasers). We demonstrate a mean time between failures (MTBF) exceeding 50,000 hours and a median life (ML) of 40,000 hours for the 10 W laser diode and a MTBF over 48,000 hours and a ML of 13,000 hours for the 20 W laser diode.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

A compact, broad beam diode based laser transmitter has been developed for moderate range and data rate free space laser communications. The laser transmitter spatially combines high average power AlGaAs laser diodes in the near field and overlaps several beams into a uniform beam in the far field. Individual high brightness laser diodes are lensed with a cylindrical lens along the length of the emitting aperture and projected with a short focal length lens into a broad beam of several milliradian divergence in the far field. The engineering prototype laser transmitter consists of six precision aligned diode assemblies, two fold mirrors and a six lenslet macrooptic assembly all mounted on a beryllium baseplate. Data will be presented showing that the laser transmitter is highly efficient by reserving the inherent high brightness of the individual diodes in the optical design, by the development of a pulsed switcher electrical circuit based on recent lightweight dc power converter designs for spacecraft applications and the removal of excess diode heat via the beryllium baseplate.

The advent of high power (> 10 Watts) 800 to 980 nm diode lasers, and medium power (1 to 10 Watts) 670 to 690 nm, and 1.8 to 2.1 micrometers diode lasers, has allowed diode lasers to enter the medical market. An overview of current, pending, and potential medical applications utilizing these lasers is presented.

Methods of reformatting the output of laser diodes and maintaining much of their intrinsic brightness are discussed. A commercial, fiber-coupled package is shown with a symmetric etendue and a brightness of 15 kW/(cm2 sr). A symmeterized beam with a brightness of 200 kW/(cm2 sr) is demonstrated by using a combination of a micro-lensed diode array and a lens array.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Recent advances in diode pump sources include higher efficiency, higher power, longer lifetimes, wider wavelength coverage, and higher operating temperatures. In addition, advances in diode array packaging have provided for higher average power capability and an optical format that is more convenient for a variety of pump applications. We discuss advances in laser performance as well as advances in packaging technology with an emphasis on pumping of high average power solid state lasers.

Results are presented on catastrophic damage limits and life-test measurements for four types of high-power laser diodes operating at wavelengths between 980 nm and 690 nm. The laser diodes under consideration are CW multimode lasers, CW laser bars, quasi-CW bars/2D stacked arrays, and single transverse mode lasers.

Ten optical fibers were aligned to a single diode laser bar. The fibers were fed through a single optical connector with an aperture diameter of 381 micrometers . Coupling efficiencies as high as 65% were achieved with antireflection-coated fibers approximately 3 cm in length. Over 6.5 W cw at a power density of 5.7 kW/cm2 was delivered from the connector output.© (1991) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Good continuous-wave lifetimes have been demonstrated for single and multiple emitter A1GaAS laser diode arrays at the highest power levels ever reported (2 watts/200 um single emitter and 10 wattst2000 multiple emitter).

Monolithic AlGaAs laser structures one cm in width and capable of 200 W peak power output with a 200 microsec pulse width have been fabricated and tested. The laser structure is similar to the single quantum well structures reported for CW bars. The devices are suitable for pumping neodymium-doped laser media.

In this letter we report the highest room-temperature cw output power of 52 W from a 1 cm monolithic diode laser array (2 mm aperture width) with no active cooling. The devices investigated have 20 ten-stripe lasers spaced on 500 μm centers, each occupying 100 μm of the facet length. The laser structures were grown by metalorganic chemical vapor deposition (MOCVD) and employed single quantum well separate confinement heterostructures. The wafers were processed to form gain-guided 6 μm-wide stripes on 10 μm centers defined by proton bombardment. Completed devices were tested under cw conditions. Several approached 50 W cw and the best laser attained 52 W before catastrophic degradation of the facet. The threshold current was 6 A and the slope efficiency was 0.89 W/A (57% differential quantum efficiency) up to approximately 40 W of optical power. The driving current required to attain output power of 52 W was 72 A. The electrical-to-optical power conversion efficiency attained 36% for an output power of 22 W and was 28% at 52 W.

cw output power levels of 76 and 55 W have been obtained from 1 cm monolithic AlGaAs laser diode arrays with an aperture width of 3 and 2 mm at a heatsink temperature of 0 and 23 °C, respectively. One of the diodes has been operated for over 5000 h at varying power levels between 5 and 10 W and at varying temperatures between 20 and 40 °C and operated successfully for over 3000 h at power levels over 7 W.