Precise control of 1.55 μm vertical-cavity surface-emitting laser structure with InAlGaAs/InAlAs Bragg reflectors by in situ growth monitoring

The vertical-cavity surface-emitting laser (VCSEL) structure designed at 1.55 mu m was grown by a low-pressure metalorganic chemical vapor deposition method. In situ laser reflectometry, using both 0.633 and 1.53 mu m wavelengths simultaneously, was employed to control the exact optical thickness over the whole growth time. The distributed Bragg reflectors (DBRs) were grown with alternate In0.53Al0.13Ga0.34As and In0.52Al0.48As lambda/4 wavelength layers. The oscillatory reflection signals obtained by the monitoring laser at 1.53 mu m gave information for designing the center wavelength of the DBR. The reflectance spectrum of the VCSEL structure showed an excellent square shaped wide flatband (greater than 90 nm) where the reflectivity reached a plateau as expected by the in situ monitoring data. (C) 1999 American Institute of Physics. [S0003-6951(99)02837-5].