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- 摘要
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- 实验方案
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Ultranarrow-waveguide AlGaAs/GaAs/InGaAs lasers
摘要： We have designed, fabricated and studied ultranarrow-waveguide heterostructure lasers emitting in the spectral range 1000 – 1100 nm. The lasers have been characterised by current – voltage, light – current, far-field intensity distribution and internal optical loss measurements. The ultranarrow-waveguide lasers have been shown to have a threshold current density of ~75 A cm–2, internal quantum efficiency near 100 % and internal optical loss near the lasing threshold under 1 cm–1, which corresponds to the level of standard heterostructures. We have demonstrated the possibility of obtaining up to 5 W of output power in continuous mode and up to 30 W in pulsed mode, with a beam convergence (FWHM) of 17.8°. The slope of the internal optical loss as a function of pump current for the ultranarrow-waveguide lasers can be markedly lower than that in lasers with a standard design, but internal quantum efficiency drops to 40 % with increasing pump current. The use of barrier layers in ultranarrow-waveguide lasers makes it possible to substantially reduce the drop in internal quantum efficiency.
关键词： absorption coefficient,internal optical loss,ultranarrow waveguide,energy barrier,pulsed pumping,semiconductor laser
更新于2025-09-11 14:15:04
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Measurements of internal optical loss inside an operating laser diode
摘要： An experimental technique for measuring internal optical loss in high-power edge-emitting semiconductor lasers is demonstrated. The technique is based on coupling a probe beam into the waveguide of a pulse-pumped laser diode. It allows measuring free-carrier absorption (FCA) in a laser heterostructure at di?erent temperatures and at pump current levels up to 30 kA/cm2. Measurement results are presented for two laser heterostructure designs, which vary in the waveguide doping level and material. For both heterostructures, the pump current increase induces a signi?cant rise in FCA and a corresponding increase in internal optical loss, from 0.4–0.7 cm?1 at the threshold current to 2–2.5 cm?1 (65 °C, 27 kA/cm2). The gradient of the FCA current dependence is lower for the laser heterostructure with a doped GaAs waveguide, while the heterostructure with an undoped AlGaAs waveguide displays a larger increase in FCA but better internal quantum e?ciency at high currents. These results show that the proposed experimental method has signi?cant potential.
关键词： internal optical loss,heterostructure,free-carrier absorption,laser diode,high-power lasers
更新于2025-09-11 14:15:04