Investigations of Optical Properties of Active Regions in Vertical Cavity Surface Emitting Lasers Grown by MBE
INSTITUTE OF ELECTRON TECHNOLOGY WARSAW(POLAND) DEPT OF PHYSICS AND TECH OF LOW DIMENSIONAL STRUCTURES
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The design of vertical cavity surface emitting lasers VCSELs requires an understanding of the many different optical parameters of these structures, and the optimization of VCSELs requires deep understanding of the optical processes occurring in the active regions of such lasers. In a series of MBE processes, active regions of VCSELs as well as whole VCSELs were grown. The active regions of the VCSEL structures were designed for lambda 1000 nanometers and 980 nanometer emission. They consisted of a pair of distributed Bragg reflectors DBRs composed of Aluminum Arsenide AlAs and Gallium Arsenide GaAs quarter wavelength layers and cavities made of GaAs. The cavities contained one or several quantum wells QWs made of In0.2Ga0.8As. To optimize the optical characteristics of the active regions, several experimental methods were applied. The Bragg reflectors and the entire microcavities were investigated by optical reflectivity. For selective excitation of a QW in a cavity active layer, a Ti-sapphire tuneable laser was used. The fine tuning between the QW emission and the cavity Fabry-Perot resonance was investigated by photoluminescence at varying temperatures of the sample. For monitoring the temporal evolution of the luminescence from the active region of the laser, time-resolved spectroscopy was employed. The combination of many methods of optical investigation enabled the authors to conduct a comprehensive characterization of VCSELs and, consequently, an optimization of the whole laser structure. 8 figures, 8 refs.
- Lasers and Masers
- Solid State Physics