OCT Imaging up to 760 kHz Axial Scan Rate Using Single- Mode 1310nm MEMS-Tunable VCSELs with>100nm

Abstract: We describe the first widely tunable, single-mode 1310nm MEMS VCSELs with>100nm tuning range, and the first application of these VCSELs to ultra-high-speed swept source OCT imaging at axial scan rates up to 760kHz. Swept source Optical Coherence Tomography (OCT) has emerged as a powerful technique for obtaining micron scale 3D images of biological tissue [1]. Emerging applications which require real-time acquisition of high-density, high volume data sets have driven the search for commercially viable swept laser sources around 1310nm with ~40 mW output power,>100nm tuning range, and several hundred kHz or higher sweep speeds [2,3]. MEMS tunable Vertical-Cavity Surface-Emitting Lasers (VCSELs) are an ideal swept source for OCT imaging, because of their micron scale cavity length and low mirror mass enabling high sweep speeds, single-mode operation without mode hops, long dynamic coherence length [4] enabling deep imaging, and compatibility with low-cost wafer-scale fabrication and testing. Though MEMS tunable VCSELs have existed for well over a decade [5,6], limited tuning range and output power have thus far precluded application to OCT. In this work we demonstrate record sweep rates and bandwidths from VCSEL sources by integrating a wide-gain InP-based quantum well active region with a GaAs-based fully oxidized mirror through wafer bonding, as shown in Figs. 1,2. A suspended top dielectric mirror moves through electrostatic actuation, generating tunable 1310nm laser emission as the structure is optically pumped at 980nm. A subsequent semiconductor optica