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Optical gain and spontaneous emission in GaAsSb–InGaAs type-II “W” laser structures

Thomson, J. D., Smowton, Peter Michael ORCID:, Blood, Peter and Klem, J. F. 2007. Optical gain and spontaneous emission in GaAsSb–InGaAs type-II “W” laser structures. IEEE Journal of Quantum Electronics 43 (7) , pp. 607-613. 10.1109/JQE.2007.899499

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The modal gain, modal loss and spontaneous emission of a GaAsSb-based type-II quantum-well (QW) laser structure emitting at 1.3 mum have been experimentally determined as a function of current injection and temperature. The system is able to provide a maximum of 900 cm-1 of material gain from the n = 1 transition despite an electron-hole overlap of 32%, however, the gain from the n = 2 transition becomes dominant before this value can be achieved. The presence of the n = 2 transition has a detrimental effect on device performance, limiting the usable gain from the first transition and increasing the total radiative recombination current. Energy level calculations show that reducing the hole QW to 4 nm would increase the separation of the n = 1 and n = 2 transition by a further 45 meV, reducing the limiting effect of the transition. Carrier distribution spectra show the carriers are in thermal equilibrium for the temperatures and injection currents studied. A low radiative efficiency for this structure is measured due to a very large nonradiative current. We believe a combination of different mechanisms contribute to the nonradiative current.

Item Type: Article
Date Type: Publication
Status: Published
Schools: Physics and Astronomy
Subjects: Q Science > QC Physics
Publisher: IEEE
ISSN: 0018-9197
Last Modified: 25 Oct 2022 09:39

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