Picosecond oscillations in multimode vertical-cavity surface-emitting semiconductor lasers

Summary form only given. We present femtosecond experiments on the emission of 850-nm GaAs multitransverse-mode VCSELs after perturbation. A single femtosecond optical pulse centered on the lasing wavelength is injected into the electrically biased VCSEL and the emission time-resolved by upconversion in a nonlinear crystal. The VCSEL spectrum at I/sub bias/=1.7/spl times/I/sub th/=10 mA shows multiple lines corresponding to multiple transverse modes and the full width at half maximum of the spectral envelope is 0.5 nm.