Berlin 2012 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 86: Semiconductor Lasers

HL 86.5: Talk

Thursday, March 29, 2012, 16:00–16:15, EW 015

Room temperature, continuous wave lasing in microcylinder and microring quantum dot laser diodes — Ferdinand Albert¹, Fabian Langer¹, Thomas Schlereth¹, Maciej Michal Pieczarka¹, Sven Höfling¹, Stephan Reitzenstein^1,2, and •Martin Kamp¹ — ¹Technische Physik, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany — ²Present address: Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstraße 36, D-10623 Berlin, Germany

Whispering gallery mode (WGM) optical resonators made of semiconductors have a wide range of applications, ranging from cavity quantum electrodynamics studies to integrated planar photonic circuits. Most of these resonators investigated so far were based on suspended microdisks supported by a pedestal with a smaller diameter. However, this geometry puts severe limitations to electrical current injection and heat removal from the resonator. Better geometries as far as these parameters are concerned are microcylinders or microrings.

We’ve achieved room temperature, continuous wave operation of laser diodes based these structures. The active region consists of six layers of InGaAs quantum dots (emission wavelength around 1.3 µ m) embedded in a quantum well. Current injection in the active part of the device is improved in ring resonators, leading to a reduction of the lasing thresholds to a few mA. This geometry also suppresses whispering gallery modes with a high radial order, thus simplifying the lasing spectra. Under these conditions, single-mode and two-color lasing can be obtained simply by adjusting the injected current.