Dilute Nitride Lasers and Spectrally Engineered Semiconductor Laser Resonators
Doktorsavhandling, 2011

The first part of this thesis deals with long wavelength (1.2-1.3 um) InGaAs(N) multiple quantum-well (QW) lasers grown on GaAs, with the aim of understanding and improving their threshold and temperature characteristics. The epitaxial material is grown by molecular beam epitaxy (MBE). By optimizing MBE growth conditions we have obtained record low values for the threshold current density of 107 and 133 A/cm^2/QW for triple QW 1.2 um InGaAs and 1.3 um GaInNAs lasers, respectively. A thorough investigation of the temperature dependence of the threshold current for ridge waveguide GaInNAs double QW lasers is presented. The good temperature stability of GaInNAs lasers is usually attributed to a large conduction band offset as well as strong defect recombination. This work, however, reveals that their good temperature stability also to a large extent arises from a significant and only weakly temperature dependent lateral diffusion current, which is not an effect intrinsic to GaInNAs but rather related to the geometry of the laser resonator. The second part explores a concept used to engineer the spectral properties of a semiconductor Fabry-Perot (FP) laser resonator. A wavelength dependent resonator loss is obtained by introducing perturbations of the effective mode index at key positions along the length of the FP resonator. In a spectrally engineered FP resonator (SE-FPR) this is used to lower the resonator loss for selected longitudinal modes which thereby require less gain for lasing. Previous treatments of SE-FPRs generally relied on an approximation valid for a weakly perturbed resonator. This work extends the treatment to also include strongly perturbed SE-FPRs. The design and fabrication of SE-FPRs supporting either one or two selected modes are investigated. For a strongly perturbed SE-FPR a very large reduction of the resonator loss can be obtained for the selected modes, with the main feedback still provided by the end facets. Fabrication tolerances are, however, strict; in particular the positioning of the perturbations with respect to the end facets is critical.

single mode laser

transfer matrix method

threshold current

InGaAs

GaAs

multiple quantum wells

dilute nitrides

two-color laser

GaInNAs

Semiconductor lasers

molecular beam epitaxy

characteristic temperature

temperature dependence

ambipolar diusion

Fabry-Perot resonator

spectral engineering

Room A423 (Kollektorn) at the Department of Microtechnology and Nanoscience -- MC2
Opponent: Prof. Eoin O'Reilly, Tyndall National Institute at University College Cork, Ireland

Författare

Göran Adolfsson

Chalmers, Mikroteknologi och nanovetenskap (MC2), Fotonik

High performance, long wavelength InGaAs/GaAs multiple quantum-well lasers grown by molecular beam epitaxy

Electronic Letters,; Vol. 43(2007)p. 454-456

Artikel i vetenskaplig tidskrift

Direct observation of lateral carrier diffusion in ridge waveguide InGaNAs lasers

IEEE Photonics Technology Letters,; Vol. 21(2009)p. 134-136

Artikel i vetenskaplig tidskrift

Effects of Lateral Diffusion on the Temperature Sensitivity of the Threshold Current for 1.3 um Double Quantum-Well GaInNAs/GaAs Lasers

IEEE Journal of Quantum Electronics,; Vol. 44(2008)p. 607-616

Artikel i vetenskaplig tidskrift

Very Low Threshold Current Density 1.29 µm GaInNAs Triple Quantum Well Lasers Grown by MBE

Electronics Letter,; Vol. 44(2008)p. 416-417

Artikel i vetenskaplig tidskrift

Spectral engineering of semiconductor Fabry–Perot laser cavities in the weakly and strongly perturbed regimes

Journal of the Optical Society of America B: Optical Physics,; Vol. 27(2010)p. 118-127

Artikel i vetenskaplig tidskrift

Styrkeområden

Nanovetenskap och nanoteknik

Ämneskategorier

Telekommunikation

Elektroteknik och elektronik

ISBN

978-91-7385489-4

Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 3170

Room A423 (Kollektorn) at the Department of Microtechnology and Nanoscience -- MC2

Opponent: Prof. Eoin O'Reilly, Tyndall National Institute at University College Cork, Ireland