Berlin 2008 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 10: Semiconductor Nanophotonics: Materials, Models, Devices - Novel Concepts

DS 10.2: Vortrag

Montag, 25. Februar 2008, 18:00–18:15, H 2032

20 W high brightness beam emission from 850 nm edge emitting lasers based on longitudinal photonic band crystal — •Thorsten Kettler¹, Kristijan Posilovic¹, Jörg Fricke², Armin Ginolas², Udo W. Pohl¹, Vitaly A. Shchukin¹, Nikolai N. Ledentsov¹, Dieter Bimberg¹, Jan Jönsson³, Markus Weyers³, and Götz Erbert² — ¹Institut für Festkörperphysik, Technische Universität Berlin — ²Ferdinand-Braun-Institut für Höchstfrequenztechnik — ³TESAG, Three-Five Epitaxial Services AG

Conventional edge emitting lasers suffer from large vertical beam divergence and are limited in maximal output power due to a narrow modal spot size of the optical mode leading to catastrophic optical mirror damage. For many applications, e.g. telecommunications, optical storage, display technology, as pump sources or for direct material processing higher brightness than available hitherto is desirable. Improving brightness at low cost is thus a key issue in research and development. We present here results from GaAs based 850 nm lasers with a one dimensional photonic band crystal (PBC) acting as an ultra broad waveguide as well as a mode filter. The structure features 4 QW and 16 periods of the PBC. It exhibits high internal efficiency of 93 % and low losses of 3 cm⁻¹, measured for broad area devices. Vertical single mode operation is observed for various stripe widths with far field divergence below 8^∘. A 50 µm wide, 1.3 mm long stripe shows a high differential efficiency of 71 % with maximal output power of 19.5 W, leading to a brightness being one of the best values ever reported.