Share Email Print

Proceedings Paper

Step-taper active-region quantum cascade lasers for carrier-leakage suppression and high internal differential efficiency
Author(s): J. D. Kirch; C.-C. Chang; C. Boyle; L. J. Mawst; D. Lindberg; T. Earles; D. Botez
Format Member Price Non-Member Price
PDF $14.40 $18.00
cover GOOD NEWS! Your organization subscribes to the SPIE Digital Library. You may be able to download this paper for free. Check Access

Paper Abstract

By stepwise tapering both the barrier heights and quantum-well depths in the active regions of 8.7 μm- and 8.4 μm-emitting quantum cascade lasers (QCLs) virtually complete carrier-leakage suppression is achieved, as evidenced by high values for both the threshold-current characteristic temperature coefficient T0 (283 K and 242 K) and the slope-efficiency characteristic temperature coefficient T1 (561 K and 279 K), over the 20–60 °C heatsink-temperature range, for low- and high-doped devices, respectively. Such high values are obtained while the threshold-current density is kept relatively low for 35-period, low- and high-doped devices: 1.58 kA/cm2 and 1.88 kA/cm2, respectively. In addition, due to resonant extraction from the lower laser level, high differential-transition-efficiency values (89-90%) are obtained. In turn, the slope-efficiency for 3 mm-long, 35-period high-reflectivity (HR)-coated devices are: 1.15-1.23 W/A; that is, 30- 40 % higher than for same-geometry and similar-doping conventional 8-9 μm-emitting QCLs. As a result of both efficient carrier-leakage suppression as well as fast and efficient carrier extraction, the values for the internal differential efficiency are found to be ≈ 86%, by comparison to typical values in the 58-67 % range for conventional QCLs emitting in the 7-11 μm wavelength range.

Paper Details

Date Published: 10 March 2016
PDF: 12 pages
Proc. SPIE 9767, Novel In-Plane Semiconductor Lasers XV, 976713 (10 March 2016); doi: 10.1117/12.2209716
Show Author Affiliations
J. D. Kirch, Univ. of Wisconsin-Madison (United States)
C.-C. Chang, Univ. of Wisconsin-Madison (United States)
C. Boyle, Univ. of Wisconsin-Madison (United States)
L. J. Mawst, Univ. of Wisconsin-Madison (United States)
D. Lindberg, Intraband, LLC (United States)
T. Earles, Intraband, LLC (United States)
D. Botez, Univ. of Wisconsin-Madison (United States)

Published in SPIE Proceedings Vol. 9767:
Novel In-Plane Semiconductor Lasers XV
Alexey A. Belyanin; Peter M. Smowton, Editor(s)

© SPIE. Terms of Use
Back to Top