Abstract

Vertical-cavity surface-emitting lasers (VCSELs) are only lasing if the emission wavelength of the quantum wells (QWs) coincides with maximum reflectivity of the Bragg reflectors. This puts stringent demands on the control of the epitaxial growth process. Additionally, it calls for a thorough characterization of the grown layer structures especially with respect to the QW emission wavelength and the spectral reflectivity of the Bragg mirrors before processing them into lasers. For this characterization optical methods are the most feasible since they are fast and usually nondestructive. We have used photoluminescence spectroscopy (PL) to characterize the emission both from the surface and from cleaved facets. This combined approach allows for a more complete characterization of the structures.

© 1994 IEEE