Berlin 2012 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 43: Poster Session: Quantum Dots and Wires - Preparation and Characterization / Devices (incl. Laser) / Ultrafast Phenomena

HL 43.23: Poster

Dienstag, 27. März 2012, 09:30–12:30, Poster D

Development of monolithic dual frequency quantum dots based semiconductor laser suitable for tunable continuous wave terahertz generation — •Vitalii Sichkovskyi, Kamen Kozhuharov, and Johann Peter Reithmaier — Technische Physik, Institute of Nanostructure Technologies and Analytics, University of Kassel, Heinrich-Plett Str. 40, D-34132 Kassel, Germany

Presently there is a considerable research activity in the development of new terahertz (THz) sources. The most promising candidate as a compact, tunable and low-cost THz emitter is the combination of a photomixer and an optical beat source. Here we report on developing of monolithic difference frequency generation source. It is designed as two coupled distributed-feedback (DFB) lasers tuned by controlling the temperature of the individual DFB laser. MBE grown laser structure consists of a GRINSCH design including single In0.60Ga0.40As QDs active layer embedded in 800 nm core waveguide surrounded by 1600 nm AlGaAs claddings layers. The broad area lasers processed from the laser structure revealed high internal quantum efficiency of 95%, low transparency current density of 139 Acm-2, high slope efficiencies > 0.45 W/A per facet, and low temperature sensitivity of the emission wavelength as low as 0.096 nm/K. Deep structure plasma etch processes for the GaAs and InP gratings of the dual-wavelength DFB lasers were developed and optimized, providing excellent anisotropy and uniformity of the structures. Platinum micro-heaters for the tuning of the lasers were fabricated and tested on RWG lasers, providing temperature increase at the ridge of 65°, at heater current of 140 mA.