The temperature dependence of key electro-optical characteristics for mid-infrared emitting quantum cascade lasers

The equations for the threshold-current density Jth, differential quantum efficiency ηd and maximum wallplug efficiency ηwp,max for quantum-cascade lasers (QCLs) have been modified for electron leakage and backfilling. We used a thermalexcitation model of "hot" injected electrons from the upper laser state to upper active-region energy states to calculate leakage currents. Then the calculated characteristic temperature T0 for Jth was found to agree well with experiment for both conventional and deep-well QCLs. The characteristic temperature T1 for ηd was deduced to be due to both electron leakage and an increase in the waveguide-loss coefficient. For conventional mid-infrared QCLs ηwp,max is found to be strongly temperature dependent which explains experimental data. By using a new concept: tapered active-region (TA), deep-well QCLs have been optimized for virtual suppression of the electron-leakage currents. In turn, at room temperature, for continuous-wave (CW)-operating, 4.5-5.0 μm-emitting TA QCLs we estimate the threshold current to decrease by ~ 25 %, the active-region temperature rise at the ηwp,max point to decrease by ~ 30 %, and the single-ended, ηwp,max value to become at least 22 %. Preliminary results from TA QCLs include T1 values as high as 454 K, over the 20-60 oC heatsink-temperature range.

[1]  Manijeh Razeghi,et al.  Room temperature continuous wave operation of quantum cascade lasers with 12.5% wall plug efficiency , 2008 .

[2]  Jérôme Faist,et al.  Wallplug efficiency of quantum cascade lasers: Critical parameters and fundamental limits , 2007 .

[3]  M. Razeghi,et al.  High-Performance Continuous-Wave Operation of $\lambda \sim {\hbox {4.6}}~\mu{\hbox {m}}$ Quantum-Cascade Lasers Above Room Temperature , 2008, IEEE Journal of Quantum Electronics.

[4]  Jerry R. Meyer,et al.  Electron leakage and its suppression via deep-well structures in 4.5- to 5.0-μm-emitting quantum cascade lasers , 2010 .

[5]  Mattias Beck,et al.  Continuous Wave Operation of a Mid-Infrared Semiconductor Laser at Room Temperature , 2001, Science.

[6]  Manijeh Razeghi,et al.  Highly temperature insensitive quantum cascade lasers , 2010 .

[7]  Qi Jie Wang,et al.  3 W Continuous-Wave Room Temperature Single-Facet Emission From Quantum Cascade Lasers Based On Nonresonant Extraction Design Approach , 2009 .

[8]  Marcella Giovannini,et al.  Gain measurements in strain-compensated quantum cascade laser , 2009 .

[9]  Federico Capasso,et al.  1.6W high wall plug efficiency, continuous-wave room temperature quantum cascade laser emitting at 4.6μm , 2008 .

[10]  D. Botez,et al.  Low temperature sensitive, deep-well 4.8 µm emitting quantum cascade semiconductor lasers , 2009, 2009 Conference on Lasers and Electro-Optics and 2009 Conference on Quantum electronics and Laser Science Conference.

[11]  Peter Michael Smowton,et al.  The differential efficiency of quantum well lasers , 1996 .

[12]  Vincenzo Spagnolo,et al.  Influence of InAs, AlAs δ layers on the optical, electronic, and thermal characteristics of strain-compensated GaInAs∕AlInAs quantum-cascade lasers , 2007 .

[13]  Karol Życzkowski,et al.  Geometry of Quantum States: Outline of quantum mechanics , 2006 .

[14]  Emmanuel Rosencher,et al.  Intersubband transitions in quantum wells , 1992 .

[15]  Dan Botez,et al.  Ultra-low temperature sensitive deep-well quantum cascade lasers (λ - 4.8 μm) via uptapering conduction band edge of injector region , 2009 .

[16]  Dan Botez,et al.  Highly temperature insensitive, deep-well 4.8 μm emitting quantum cascade semiconductor lasers , 2009 .

[17]  Vincenzo Spagnolo,et al.  Simultaneous measurement of the electronic and lattice temperatures in GaAs/Al0.45Ga0.55As quantum-cascade lasers: Influence on the optical performance , 2004 .

[18]  Jerry R. Meyer,et al.  Temperature dependence of the key electro-optical characteristics for midinfrared emitting quantum cascade lasers , 2010 .

[19]  Mattias Beck,et al.  High-temperature operation of distributed feedback quantum-cascade lasers at 5.3 μm , 2001 .

[20]  Manijeh Razeghi,et al.  Quantum cascade lasers that emit more light than heat , 2010 .

[21]  Manijeh Razeghi,et al.  High-power high-wall plug efficiency mid-infrared quantum cascade lasers based on InP/GaInAs/InAlAs material system , 2009, OPTO.

[22]  Federico Capasso,et al.  High power thermoelectrically cooled and uncooled quantum cascade lasers with optimized reflectivity facet coatings , 2009 .

[23]  Dan Botez,et al.  InGaAs/GaAsP/AlGaAs, deep-well, quantum-cascade light-emitting structures grown by metalorganic chemical vapor deposition , 2008 .

[24]  Manijeh Razeghi,et al.  Room temperature continuous wave operation of quantum cascade lasers with watt-level optical power , 2008 .

[25]  Yamac Dikmelik,et al.  Limitations to the power output and efficiency of mid-Infrared quantum cascade lasers imposed by transport , 2010, CLEO/QELS: 2010 Laser Science to Photonic Applications.

[26]  P. Collot,et al.  Quantum Cascade Lasers , 1997, CLEO/Europe Conference on Lasers and Electro-Optics.

[27]  Jacob B. Khurgin,et al.  Highly power-efficient quantum cascade lasers , 2010 .

[28]  Federico Capasso,et al.  Activation energy study of electron transport in high performance short wavelengths quantum cascade lasers. , 2010, Optics express.