Data are presented showing that thermal annealing (875–-900 °C) can be used to modify the wavelength of a photopumped, low threshold AlxGa1−xAs quantum well heterostructure (QWH) laser from ∼8200 to ∼7300 Å with a threshold change from 150 to 1700 W/cm2. The energy levels of the annealed single quantum well crystal are approximated by fitting a modified Pöschl–Teller potential to the band-edge profile as modified by layer (Al–Ga) interdiffusion. The layer (Al–Ga) interdiffusion coefficient (at 875 °C) is found to be smaller, by a factor of 3–4, than previously reported. We suggest that this is due to the high quality, i.e., low defect density, of the ultralow threshold QWH crystals of this work.
Data are presented showing that it is possible to photopump and operate a quantum well heterostructure laser at equivalent current densities (Jeq) as low as 70 A/cm2. Continuous 300-K laser operation of a single 60-Å GaAs (x=0) quantum well in the center of a ∼0.12-μm-thick x′∼0.30 Alx′Ga1−x′As waveguide (and carrier reservoir), which is confined by x″∼0.85 Alx″Ga1−x″As layers, is demonstrated at Ieq∼0.4 mA (168 W/cm2, Jeq∼70 A/cm2). These quantum well heterostructures are grown by organometallic vapor phase epitaxy.
A phase-locked multiple quantum well (GaAl)As injection laser is demonstrated to emit over 1.5 W/mirror (>3 W total) cw output power at ∼8350 Å with a maximum power conversion efficiency of 17.4%.
A gain-guided phase-locked semiconductor laser array has been observed to emit a single narrow lobed far-field radiation pattern up to 70 mW, at which power level it exhibits a distinct change. We show that this effect results from a new phase-locked mode attaining threshold; the original mode remains phase locked above this power level.
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