Frequency response of large aperture oxide-confined 850 nm vertical cavity surface emitting lasers

Small and large signal modulation measurements are carried out for 850 nm vertical cavity surface emitting lasers (VCSELs). The resonance frequency, damping factor, parasitic frequency, and D-factor are extracted. Small signal modulation bandwidths larger than 20 GHz are measured. At larger currents the frequency response becomes partially limited by the parasitics and damping. Our results indicate that by increasing the parasitic frequency, the optical 3 dB bandwidth may be extended to ∼25 GHz. A decrease in the damping should enable VCSEL bandwidths of 30 GHz for current densities not exceeding ∼10 kA/cm2 and ultimately error-free optical links at up to 40 Gbit/s.