Dresden 2009 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 35: Semiconductor Laser

HL 35.4: Talk

Wednesday, March 25, 2009, 14:45–15:00, BEY 154

Power limiting effects in 2.X µm emitting GaSb-based Diode-Lasers — •Markus Müller, Marcell Rattunde, Johannes Schmitz, Gudrun Kaufel, and Joachim Wagner — Fraunhofer-Institut für Angewandte Festkörperphysik, Tullastrasse 72, D-79108 Freiburg, Germany

Semiconductor lasers emitting around 2 µm are of interest for a range of applications including material processing, medical diagnostics and therapy or trace gas sensing. (AlGaIn)(AsSb)-based quantum well lasers are well suited for the 1.8-2.4 µm wavelength range as they exhibit excellent lasing characteristics.

Under CW operation the output power of GaSb-based diode lasers is limited by thermal rollover due to self-heating of the active region. To suppress this thermal effect in order to explore the high-power characteristics we analyzed these lasers under pulsed mode operation using 20 ns to 2 µs long current pulses. This way we reached optical pulse power above 16 W from a single-emitter when driven with current pulses up to 100 A. Simultaneously, we performed time-resolved measurements of the lasing spectra (3 ns time frame) in order to deduce remaining self-heating effects from the shift of the lasing spectrum.

The results obtained clearly demonstrate that the high current high power performance of GaSb-based 2.X µm diode lasers is limited by self-heating effects even under short pulse operation. In contrast to GaAs-based devices emitting around 1 µm, no catastrophic optical mirror damage (COMD) is observed even at the highest power densities at the facet of 16 MW/cm².