Facet temperature mapping of GaAs/AlGaAs quantum cascade lasers by photoluminescence microprobe

• Published in: Optical materials Vol. 17; no. 1; pp. 219 - 222
• Main Authors: Spagnolo, V., Troccoli, M., Scamarcio, G., Becker, C., Glastre, G., Sirtori, C.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.06.2001; Elsevier Science
• Subjects: Exact sciences and technology; Facet temperature mapping; Fundamental areas of phenomenology (including applications); Lasers; Optics; Physics; Quantum cascade laser; Semiconductor lasers; laser diodes; Thermal resistance; Thermal resistance; Facet temperature mapping; Quantum cascade laser; Aluminium arsenides; Temperature measurement; Gallium arsenides; Semiconductor lasers; Ternary compounds; Photoluminescence; Thermal resistance measurement; Binary compounds; Experimental study; Quantum cascade lasers
• ISSN: 0925-3467; 1873-1252
• DOI: 10.1016/S0925-3467(01)00083-0

The measurement of thermal resistance and facet temperature profile of operating GaAs/AlGaAs quantum cascade lasers (QCLs) as a function of injected current, repetition rate and pulse width is reported. The use of microprobe band-to-band photoluminescence (PL) spectroscopy allows to achieve a spatial resolution <1 μm. Substrate-side and epilayer-side mounted devices with identical laser structures were investigated. At T=80 K, the thermal resistance of epilayer-side mounted devices (7.8 K/W) is ∼30% lower than that of substrate-side mounted devices, thus explaining the better performance of the former. The outcome of a two-dimensional model of heat propagation in our structures is compared with the experimental data.