Energy efficient microcavity lasers with 20 and 40 Gb/s data transmission

Microcavity lasers $(μCLs)$⁠, reduced-size (⁠$≲3μm$ aperture) vertical cavity surface-emitting lasers (VCSELs) defined by the buried-oxide process for current and field confinement (thus wide mode spacing), are demonstrated with low threshold current, sharp turn-on $L-I$ characteristics, and wide bandwidth operation. Due to the enhanced spontaneous recombination rate at reduced mode and improved photon density, $μCLs$ exhibit lower charge-field resonance peaks at a modulation bandwidth $f−3dB=18.7GHz$⁠, thus permitting open-“eye” operation at 20 and 40 Gb/s data rates $(I≲3mA)$⁠. The energy efficiency for 20 Gb/s data transmission is measured to be 4.84 Gb/s/mW, which is eight times better than $7μm$ aperture VCSELs.