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Optical Engineering • Open Access • new

Design considerations for λ ∼ 3.0- to 3.5-μm-emitting quantum cascade lasers on metamorphic buffer layers
Author(s): Ayushi Rajeev; Chris Sigler; Thomas L. Earles; Yuri V. Flores; Luke J. Mawst; Dan Botez

Paper Abstract

Quantum cascade lasers (QCLs) that employ metamorphic buffer layers as substrates of variable lattice constant have been designed for emission in the 3.0- to 3.5-μm wavelength range. Theoretical analysis of the active-region (AR) energy band structure, while using an 8-band k•p model, reveals that one can achieve both effective carrier-leakage suppression as well as fast carrier extraction in QCL structures of relatively low strain. Significantly lower indium-content quantum wells (QWs) can be employed for the AR compared to QWs employed for conventional short-wavelength QCL structures grown on InP, which, in turn, is expected to eliminate carrier leakage to indirect-gap valleys (X, L). An analysis of thermo-optical characteristics for the complete device design indicates that high-Al-content AlInAs cladding layers are more effective for both optical confinement and thermal dissipation than InGaP cladding layers. An electroluminescence-spectrum full-width half-maximum linewidth of 54.6 meV is estimated from interface roughness scattering and, by considering both inelastic and elastic scattering, the threshold-current density for 3.39-μm-emitting, 3-mm-long back-facet-coated QCLs is projected to be 1.40  kA/cm2.

Paper Details

Date Published: 27 September 2017
PDF: 10 pages
Opt. Eng. 57(1) 011017 doi: 10.1117/1.OE.57.1.011017
Published in: Optical Engineering Volume 57, Issue 1
Show Author Affiliations
Ayushi Rajeev, Univ. of Wisconsin-Madison (United States)
Chris Sigler, Univ. of Wisconsin-Madison (United States)
Thomas L. Earles, Intraband LLC (United States)
Yuri V. Flores, Massachusetts Institute of Technology (United States)
Luke J. Mawst, Univ. of Wisconsin-Madison (United States)
Dan Botez, Univ. of Wisconsin-Madison (United States)

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