Nanoscale Research Letters (Feb 2018)

Stable Single-Mode Operation of Distributed Feedback Quantum Cascade Laser by Optimized Reflectivity Facet Coatings

  • Dong-Bo Wang,
  • Jin-Chuan Zhang,
  • Feng-Min Cheng,
  • Yue Zhao,
  • Ning Zhuo,
  • Shen-Qiang Zhai,
  • Li-Jun Wang,
  • Jun-Qi Liu,
  • Shu-Man Liu,
  • Feng-Qi Liu,
  • Zhan-Guo Wang

DOI
https://doi.org/10.1186/s11671-018-2455-z
Journal volume & issue
Vol. 13, no. 1
pp. 1 – 7

Abstract

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Abstract In this work, quantum cascade lasers (QCLs) based on strain compensation combined with two-phonon resonance design are presented. Distributed feedback (DFB) laser emitting at ~ 4.76 μm was fabricated through a standard buried first-order grating and buried heterostructure (BH) processing. Stable single-mode emission is achieved under all injection currents and temperature conditions without any mode hop by the optimized antireflection (AR) coating on the front facet. The AR coating consists of a double layer dielectric of Al2O3 and Ge. For a 2-mm laser cavity, the maximum output power of the AR-coated DFB-QCL was more than 170 mW at 20 °C with a high wall-plug efficiency (WPE) of 4.7% in a continuous-wave (CW) mode.

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