Temperature insensitive quantum dot structures for vertical cavity lasers

Abstract

Summary form only given. Quantum dot structures are now being incorporated within vertical cavity surface emitting lasers (VCSELs). The use of quantum dots within these structures offers the potential of achieving 1.3 /spl mu/m wavelengths with GaAs based materials. Theoretically the realisation of quantum dot VCSELs would seem to be extremely difficult as they require the alignment of a single energy state emitter with a cavity mode. In practice this may be achieved because of the inhomogeneous broadening of the dot gain spectrum due to size fluctuations which gives a broad lineshape. This lineshape function can also enhance the operation of VCSELs in that it produces a very low spectral shift of the gain spectrum with temperature. We present measurements of optical gain within InGaAs quantum dots emitting at /spl sim/1 /spl mu/m wavelengths which confirm that this is so. Indeed the results show a shift in the gain which matches that seen for the lasing mode within vertical cavity structures at this wavelength.