High-performance quantum cascade lasers: optimized design through waveguide and thermal modeling

Scott S. Howard, Zhijun Liu, Daniel Wasserman, Anthony J. Hoffman, Tiffany S. Ko, Claire F. Gmachl

Research output: Contribution to journalArticlepeer-review

52 Scopus citations


We present a comprehensive model to study the thermal effects in quantum cascade (QC) lasers for continuous-wave (CW) operation at and above room temperature. This model self-consistently solves the temperature-dependent threshold current density equation and heat equation to determine the CW threshold current density, maximum heat sink temperature, and core temperature at threshold for a given laser design. The model includes effects from temperature dependence on thermal backfilling, thermal conductivity, phonon lifetimes, gain bandwidth, thermionic emission, and resistive heating in waveguide layers. Studies on these effects yield results not simultaneously considered by previous models. By including these results in laser designs, lasers with lower core temperatures, with higher operating temperatures, and requiring lower electrical power than current high-performance lasers are predicted. Additionally, experimental results are presented, exploring various methods of improving CW laser performance for a λ∼8 μm QC laser and are compared to the model.

Original languageEnglish (US)
Pages (from-to)1054-1064
Number of pages11
JournalIEEE Journal on Selected Topics in Quantum Electronics
Issue number5
StatePublished - Sep 2007

All Science Journal Classification (ASJC) codes

  • Atomic and Molecular Physics, and Optics
  • Electrical and Electronic Engineering


  • High performance
  • Quantum cascade (QC) laser
  • Semiconductor laser
  • Thermal modeling


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