Berlin 2005 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 24: Bauelemente
HL 24.1: Vortrag
Samstag, 5. März 2005, 10:45–11:00, TU P-N229
Ultrafast carrier dynamics in an InAs quantum-dot amplifier emitting at 1.3 µm — •Sabine Dommers1, Stephan Schneider1, Ulrike Woggon1, Paola Borri2, Wolfgang Langbein3, Thorsten Kettler4, Matthias Lämmlin4, and Dieter Bimberg4 — 1Universität Dortmund, Otto-Hahn-Str. 4, 44221 Dortmund, Germany — 2School of Biosciences, Cardiff University, Main Building, Park Place, Cardiff CF10 3TL, UK — 3Department of Physics and Astronomy, Cardiff University, 5 The Parade, Cardiff CF24 3YB, UK — 4Institut für Festkörperphysik, TU Berlin, 10623 Berlin, Germany
InAs quantum-dot amplifiers (QDA) can show improved performances over well or bulk devices. The investigated QDA with a ground-state (GS) emission wavelength of 1.3 µm is appealing for optical communication technology. We measure the ultrafast carrier dynamics at the GS and the linewidth enhancement factor (LEF) α at room temperature. The QDA is a p-i-n narrow ridge waveguide structure with InAs quantum-dots in the active region. Using differential transmission spectroscopy, with heterodyne detection, absorption/gain and refractive index dynamics are studied. The LEF α is determined from measurements of the modal gain g and the refractive index Δn. Resonant to the GS the LEF α is 0.02 for low bias current and becomes zero or even negative for higher transition energies [1]. These results are promising for low chirp operation and supression of beam filamentation. We also find that the gain recovery dynamics is suitable for signal processing at high bit-rates with recovery time constants of some ps [2]. [1] S. Schneider et al. IEEE J. Q. El. 40, 1423 (2004) [2] P. Borri et al. IEEE J.Sel.Top. Q. El. 8, 984 (2002)