Title :
Gain and threshold characteristics of long wavelength lasers based on InAs/GaAs quantum dots formed by activated alloy phase separation
Author :
Maximov, M.V. ; Asryan, L.V. ; Shernyakov, Yu.M. ; Tsatsul´nikov, A.F. ; Kaiander, I.N. ; Nikolaev, V.V. ; Kovsh, A.R. ; Mikhrin, S.S. ; Ustinov, V.M. ; Zhukov, A.E. ; Alferov, Zh.I. ; Ledenstou, N.N. ; Bimberg, D.
Author_Institution :
Inst. fur Festkorperphys., Tech. Univ. Berlin, Germany
fDate :
5/1/2001 12:00:00 AM
Abstract :
Experimental and theoretical study was made of injection lasers based on InAs/GaAs quantum dots (QDs) formed by the activated alloy phase separation and emitting at about 1.3 μm. Electroluminescence and gain spectra were investigated. The maximum modal gain is measured experimentally using two different techniques. Threshold current densities as low as 22 A cm-2 per QD sheet were achieved. A step-like switch from ground- to excited-state transition lasing was observed with an increasing cavity loss. The characteristic temperatures for a sample with four cleaved sides and a 2-mm long stripe device at 300 K were 140 and 83 K, respectively. Single lateral-mode continuous-wave (CW) operation with the maximum output power of 210 mW was realized. Threshold characteristics of a laser were simulated taking into account radiative recombination in QDs, the wetting layer, and the optical confinement layer. The dependence of the threshold current density on the cavity length was shown to be extremely sensitive to the QD-array parameters determining the maximum gain for ground- and excited-state transitions and to the waveguide design. Our analysis reveals that nonradiative recombination channels may play an important role in the laser operation
Keywords :
Debye temperature; III-V semiconductors; current density; electroluminescence; excited states; gallium arsenide; ground states; indium compounds; laser beams; laser cavity resonators; laser modes; laser transitions; laser variables measurement; optical losses; phase separation; quantum well lasers; semiconductor quantum dots; waveguide lasers; 1.3 mum; 2 mm; 210 mW; 300 K; InAs-GaAs; InAs/GaAs quantum dots; activated alloy phase separation; cavity length; cavity loss; characteristic temperatures; cleaved sides; electroluminescence spectra; excited-state transition lasing; excited-state transitions; gain characteristics; gain spectra; ground-state transition lasing; ground-state transitions; injection lasers; laser operation; long wavelength lasers; maximum gain; maximum modal gain; maximum output power; nonradiative recombination channels; optical confinement layer; quantum well-array parameters; radiative recombination; single lateral-mode continuous-wave operation; step-like switch; stripe device; threshold characteristics; threshold current densities; threshold current density; waveguide design; wetting layer; Electroluminescence; Gallium arsenide; Laser theory; Laser transitions; Optical waveguides; Quantum dot lasers; Quantum mechanics; Radiative recombination; Switches; Threshold current;
Journal_Title :
Quantum Electronics, IEEE Journal of
