High Injection Effects in Quantum Well Lasers
While quantum well lasers offer the attractive feature of tuning the wavelength by adjusting the well width, interest in these devices is also stimulated by the reductions in threshold current which are predicted compared with conventional double heterostructure devices.1 Many of the predictions of threshold current (Ith) are based on ideal rectangular density of states functions,2 yet such calculations do not account for the observation that the laser emission occurs at a longer wavelength than that associated with the appropriate sub-band separation.3 Although some calculations have included intra-band scattering,4 or have relaxed the k-selection rules,5 these still fail to reproduce the wavelength behaviour correctly.
KeywordsLaser Emission Threshold Current Gain Spectrum Threshold Current Density Width Fluctuation
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- 1.For a recent review of the physics of quantum well lasers see: P. Blood, Reappraisal of GaAs-AlGaAs quantum well lasers, in Quantum Wells and Superlattices in Optoelectronic Devices and Integrated Optics, A.R. Adams ed, Proc SPIE 861, 34–41 (1987).Google Scholar
- 14.P. Blood, E.D. Fletcher, K. Woodbridge, K.C. Heasman and A.R. Adams, Influence of the barriers on the temperature dependence of threshold current in GaAs/AalGaAs quantum well lasers. To be published.Google Scholar
- 16.D.J. Robbins, Lifetime broadening in quantum well lasers, in Novel Optoelectronic Devices, M.J. Adams ed, Proc. SPIE 800:34 (1987).Google Scholar