Fundamental mode operation has been achieved in a large area oxide-confined
vertical-cavity surface-emitting laser (VCSEL) by etching a shallow surfac
e relief in the top mirror. The nonlinear distortion during analog modulati
on has been measured and compared to the distortion in a planar multimode V
CSEL, The distortion was quantified by conventional two-tone measurements f
rom which the spurious free dynamic range was determined. Several decibels
improvement in dynamic range was observed in the low frequency range (0.1-2
GHz) for the single-mode VCSEL, This is primarily due to a higher relaxati
on frequency and an absence of mode competition and mode partition noise in
the single-mode VCSEL, indicating the advantages of using single-mode VCSF
ELs for high-performance analog modulation.