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Proceedings Paper

Radiative efficiency of MOCVD grown QD lasers
Author(s): Luke Mawst; Gene Tsvid; Peter Dudley; Jeremy Kirch; J. H. Park; N. Kim
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Paper Abstract

The optical spectral gain characteristics and overall radiative efficiency of MOCVD grown InGaAs quantum dot lasers have been evaluated. Single-pass, multi-segmented amplified spontaneous emission measurements are used to obtain the gain, absorption, and spontaneous emission spectra in real units. Integration of the calibrated spontaneous emission spectra then allows for determining the overall radiative efficiency, which gives important insights into the role which nonradiative recombination plays in the active region under study. We use single pass, multi-segmented edge-emitting in which electrically isolated segments allow to vary the length of a pumped region. In this study we used 8 section devices (the size of a segment is 50x300 μm) with only the first 5 segments used for varying the pump length. The remaining unpumped segments and scribed back facet minimize round trip feedback. Measured gain spectra for different pump currents allow for extraction of the peak gain vs. current density, which is fitted to a logarithmic dependence and directly compared to conventional cavity length analysis, (CLA). The extracted spontaneous emission spectrum is calibrated and integrated over all frequencies and modes to obtain total spontaneous radiation current density and radiative efficiency, ηr. We find ηr values of approximately 17% at RT for 5 stack QD active regions. By contrast, high performance InGaAs QW lasers exhibit ηr ~50% at RT.

Paper Details

Date Published: 25 February 2010
PDF: 8 pages
Proc. SPIE 7597, Physics and Simulation of Optoelectronic Devices XVIII, 759716 (25 February 2010); doi: 10.1117/12.840970
Show Author Affiliations
Luke Mawst, Univ. of Wisconsin-Madison (United States)
Gene Tsvid, Univ. of Wisconsin-Madison (United States)
Peter Dudley, Univ. of Wisconsin-Madison (United States)
Jeremy Kirch, Univ. of Wisconsin-Madison (United States)
J. H. Park, Univ. of Wisconsin-Madison (United States)
N. Kim, Univ. of Wisconsin-Madison (United States)

Published in SPIE Proceedings Vol. 7597:
Physics and Simulation of Optoelectronic Devices XVIII
Bernd Witzigmann; Fritz Henneberger; Yasuhiko Arakawa; Marek Osinski, Editor(s)

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