Vertical-cavity surface-emitting 1.55-$\mu$m lasers fabricated by fusion

The results of studies on fabrication of vertical-cavity surface-emitting 1.55-$\mu$m lasers by fusing AlGaAs/GaAs distributed-Bragg-reflector wafers and an active region based on thin In$_{0.74}$Ga$_{0.26}$As quantum wells grown by molecular-beam epitaxy are presented. Lasers with a current aperture diameter of 8 $\mu$m exhibit continuous lasing with a threshold current below 1.5 mA, an output optical power of 6 mW, and an efficiency of approximately 22%. Single-mode lasing with a side-mode suppression ratio of 40–45 dB is observed in the entire operating current range. The effective modulation frequency of these lasers is as high as 9 GHz and is limited by the low parasitic cutoff frequency and self-heating.