S. Arslan, A. Boni, A. Maaßdorf, G. Erbert, D. Martin, J. Fricke and P. Crump
Conf. on Lasers and Electro-Optics/Europe and European Quantum Electronics Conf. (CLEO/Europe-EQEC 2021), Munich, Germany, Jun. 21-25, virtual event, ISBN: 978-1-6654-1876-8, cb-2-4 (2021).
High-power GaAs-based diode lasers are the most efficient light sources and thus used in many industrial applications. Higher peak output power (Popt) and efficiency (ηE) are sought to reduce operating cost (€/W)  , but Popt is limited by a range of interacting saturation mechanisms. Improved experimental diagnosis of the dominant effects with lateral and longitudinal hole-burning effects playing a key role is needed and ways to address these issues need to be found  . For a given device construction, improvements to the (vertical) epitaxial layer design can lead to strong improvements in both Popt and ηE. Here, we study devices with resonator length L = 4 mm and stripe width W = 90 µm, mounted junction down on CuW carriers, with operating wavelength λ ∼ 970 nm. As previously reported, although such L = 4 mm, W = 90 µm devices show high peak ηE when using asymmetric large optical cavity (ASLOC) epitaxial designs, both Popt and ηE are strongly improved through the use of extreme triple asymmetric (ETAS) designs. These ETAS designs use thin p-side waveguide and asymmetric graded index layers in the vicinity of the quantum well (QW) to reduce series resistance, carrier leakage and optical loss  . In a previous study, it is shown that compared to the ASLOC structure Popt and ηE increases from 14 W to 19 W and 65% to 67%, respectively, at 25 °C under continuous wave (CW) operation using ETAS structures.
Ferdinand-Braun-Institut gGmbH, Leibniz Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Straße 4, 12489 Berlin, Germany
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