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High Power Quantum Dot Lasers at 1160 nm
Author(s) -
Ribbat Ch.,
Sellin R.,
Grundmann M.,
Bimberg D.
Publication year - 2001
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/(sici)1521-3951(200104)224:3<819::aid-pssb819>3.0.co;2-1
Subject(s) - lasing threshold , laser , excited state , quantum dot laser , quantum dot , optoelectronics , rate equation , materials science , spontaneous emission , wavelength , spectral line , radiative transfer , semiconductor laser theory , atomic physics , physics , optics , quantum mechanics , kinetics
Improved device characteristics of high‐power InGaAs/GaAs quantum dot (QD) lasers are presented. An ideal internal quantum efficiency close to 100%, very low transparency current density of 18 A/cm 2 and a peak power close to 4 W at 1155 nm lasing wavelength in pulsed operation at room temperature are demonstrated. The improvement of the devices is mainly due to the reduction of non‐radiative recombination centres in the GaAs matrix around the dots. The lasing spectra for different driving currents are presented and compared to theoretical calculations based on master equations for the micro‐states (MEM) coupled to the rate equations for the photon density. From the maximum width of the lasing spectra under high driving currents (18 nm) the fraction of QDs that contribute to the lasing emission is deduced. For different lasers the maximum ground (excited) state gain is found to be 13.6 cm —1 (34 cm —1 ), respectively, via a fit of the QD gain‐current dependence according to the MEM theory.