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Since the first demonstration of swept source optical coherence tomography (SS-OCT) imaging using widely tunable micro-electromechanical systems vertical cavity surface-emitting lasers (MEMS-VCSELs) in 2011, VCSEL-based SS-OCT has advanced in both device and system performance. These advances include extension of MEMS-VCSEL center wavelength to both 1060nm and 1300nm, improved tuning range and tuning speed, new SS-OCT imaging modes, and demonstration of the first electrically pumped devices. Optically pumped devices have demonstrated continuous singlemode tuning range of 150nm at 1300nm and 122nm at 1060nm, representing a fractional tuning range of 11.5%, which is nearly a factor of 3 greater than the best reported MEMS-VCSEL tuning ranges prior to 2011. These tuning ranges have also been achieved with wavelength modulation rates of >500kHz, enabling >1 MHz axial scan rates. In addition, recent electrically pumped devices have exhibited 48.5nm continuous tuning range around 1060nm with 890kHz axial scan rate, representing a factor of two increase in tuning over previously reported electrically pumped MEMS-VCSELs in this wavelength range. New imaging modes enabled by optically pumped devices at 1060nm and 1300nm include full eye length imaging, pulsatile Doppler blood flow imaging, high-speed endoscopic imaging, and hand-held wide-field retinal imaging.

We describe tunable vertical cavity surface emitting lasers with a half-symmetric cavity structure. The cavity is realized by inducing a curvature (R∼300 μm) in the top movable dielectric mirror. This half-symmetric microcavity forces lasing oscillations in a single fundamental spatial mode with a side-mode suppression ratio of >25 dB. Continuous wavelength tuning of 44 nm was achieved microelectromechanically with a tuning voltage of 14 V. The device operates near 950 nm with maximum power output of ∼0.9 mW.