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Proceedings Paper

High-performance 1300-nm InAs/GaAs quantum-dot lasers
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Paper Abstract

Quantum dot (QD) lasers incorporating the dot-in-a-well (DWELL) structures offer the prospect of lowcost and high-performance sources for telecom applications at 1300 nm. A number of significant advantages have been demonstrated to arise from the 0-D density of states, such as low threshold, low noise, low chirp and relative temperature insensitivity. However QD lasers suffer from a low modal gain per dot layer, which is a major factor of limiting high-speed performance. To address this, both a high inplane dot density and the use of multilayer structure are necessary and this presents a major challenge for molecular beam epitaxy (MBE) growth. In this work, to increase the gain of 1300-nm quantum-dot (QD) lasers, we first optimize the MBE growth of InAs/InGaAs QD structure for single-layer epitaxy structure with In composition within InGaAs well. Then we proposed a growth technique, high-growthtemperature spacer layer to suppress the dislocation formation for the multilayer QD structure. These lead to the realization of high-performance multilayer 1300-nm QD lasers with extremely low threshold current density (Jth) of 17 A/cm2 at room temperature (RT) under continuous-wave (cw) operation and high output power of over 100 mW. By combining the high-growth-temperature spacer layer technique with the p-type modulation doping structure, a negative characteristic temperature above RT has been demonstrated for a 5-layer QD laser structure. Further modification of the high-growth-temperature spacer layer technique, we realized a very low RT threshold current density of 33 A/cm2 for a 7-layer ptype- modulated QD laser. The temperature coefficient of ~0.11 nm/K over the temperature range from 20 to 130 °C has also been realized by modifying the strain profile of InGaAs capping layer. These techniques could find application in lasers designed for optical fiber systems.

Paper Details

Date Published: 29 January 2008
PDF: 11 pages
Proc. SPIE 6909, Novel In-Plane Semiconductor Lasers VII, 690903 (29 January 2008); doi: 10.1117/12.765735
Show Author Affiliations
H. Y. Liu, Univ. College London (United Kingdom)
Univ. of Sheffield (United Kingdom)
M. Hopkinson, Univ. of Sheffield (United Kingdom)
K. Groom, Univ. of Sheffield (United Kingdom)
R. A. Hogg, Univ. of Sheffield (United Kingdom)
D. J. Mowbray, Univ. of Sheffield (United Kingdom)

Published in SPIE Proceedings Vol. 6909:
Novel In-Plane Semiconductor Lasers VII
Alexey A. Belyanin; Peter M. Smowton, Editor(s)

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