Thermal resistance and temperature characteristics of GaAs/Al0.33Ga0.67As quantum-cascade lasers

Abstract

We report on the determination of thermal resistance, facet temperature profile, and heat flux of GaAs/Al0.33Ga0.67As quantum-cascade lasers operating in pulsed mode, using a microprobe band-to-band photoluminescence technique. The thermal resistance of epilayer-side mounted lasers is ∼30% smaller than that of substrate-side mounted ones. The dependence of the thermal resistance on the injection conditions and its correlation with the output power is also reported.

Switching operation of lasing wavelength in mid-infrared ridge-waveguide quantum cascade lasers coupled with microcylindrical cavity

“…18 However the values we obtained seem to be reasonable, considering that R th also strongly depends on the excitation condition ͓10%-duty cycle in Ref. 18 and 0.04% ͑0.08%͒ for the ridgewaveguide cavity ͑the microcavity͒ in our experiments͔. In fact, Fig.…”

“…4͑a͒ in Ref. 18 indirectly indicates that the thermal resistance in the 10%-duty cycle condition is a few times larger than that in the Ͻ1%-duty cycle condition.…”

“…Here, it is difficult to estimate R th accurately from the structural parameters of the cavity because of the uncertain value of the anisotropic heat conductivity in the multilayerd active region. 15,[18][19][20] Therefore, we calculated R th backward which makes ⌬n eff equal to 0.003, and obtained R th of 3.9 K/W for the ridge-waveguide cavity and of 5.1 K/W for the microcavity. Here, we substituted the literature value dn / dT Ϸ 1 ϫ 10 −4 K −1 for GaAs at 100 K 21 and the measured values ⌬P ridge = 7.77 W͓⌬P = I ϫ V ͑I=1.3I th ͒ ͑1.77 A ϫ 15.78 V͒ − I ϫ V ͑I=1.05I th ͒ ͑1.40 A ϫ 14.40 V͔͒ and ⌬P micro = 5.92 W͓⌬P = I ϫ V ͑I=600 mA͒ ͑0.6 A ϫ 9.86 V͔͒.…”

Influence of Operating Conditions on Quantum Cascade Laser Temperature

“…The most common solution is the realization of buried heterostructures 5,6 or processing optimization. 7 Many experimental techniques are used for thermal characterization of QCLs (e.g., microphotoluminescence, [8][9][10] Raman spectroscopy, 11 and thermoreflectance spectroscopy 12 ). In this work, spatially resolved thermoreflectance spectroscopy (SRTR) 13 was used to determine the temperature distribution on QC laser facet.…”

Advances in High-Power Laser Diode Packaging

“…Especially for single-mode (≤4 µm) ridge-waveguide laser diodes, the bulk of the heat generation is confined within the active region. This raises concerns as significant heat accumulation in the active region influences the spectral and spatial characteristics, with longitudinal modes broadening (Spagnolo et al, 2001). The optical output power will also be compromised since their performance characteristics are sensitive to the operating temperature of the laser diode.…”