Optimizing Vertical and Lateral Waveguides of kW-Class Laser Bars for Higher Peak Power, Efficiency and Lateral Beam Quality
Md. J. Miah, A. Boni, S. Arslan, D. Martin, P. Della Casa, and P. Crump
IEEE Photonics J., vol. 14, no. 3, art. 1525505, doi:10.1109/JPHOT.2022.3165399 (2022).
GaAs-based, highly-efficient, kW-class, 1-cm laser bars with high peak power Popt and improved beam quality in quasi-continuous-wave mode are presented. The use of an extreme-triple-asymmetric (ETAS) epitaxial layer structure diminishes power saturation of high-power bars at high driving current. The resulting ETAS bars with 4 mm cavity produce a record 1.9 kW peak power, limited by available current supply, with a maximum power conversion efficiency ηE = 67% at THS = 25 °C heat-sink temperature. Both Popt and ηE have been increased further by operating the bars at THS = -70 °C. Sub-zero operation raises the Popt to 2.3 kW and the maximum ηE to 74%. A second configuration of ETAS bars with optimized lateral layout is further realized to obtain narrow lateral beam divergence Θ up to 2 kA driving current, without sacrificing Popt and ηE. A 2-3° lower Θ (95% power level) is observed over a wide operating range at room temperature. A high degree of polarization is also maintained across the whole operating range.
Ferdinand-Braun-Institut gGmbH, Leibniz-Institut für Höchstfrequenztechnik, 12489 Berlin, Germany
Beam quality, beam parameter product, diode lasers, high efficiency, high-power lasers, laser bars, near field, far field, semiconductor lasers.
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