VCSEL swept light sources

Abstract

Wavelength–swept light sources are widely recognized as a critical enabling technology for swept source optical coherence tomography (SS–OCT). In recent years, amplified micro–electromechanical systems tunable vertical cavity surface–emitting lasers (MEMS–VCSELs) have emerged as a high performance swept source, providing a unique combination of of wide tuning range, high maximum sweep rate, variable sweep rate, long dynamic coherence length enabled by dynamic mode–hop–free single mode operation, high optical power, and excellent imaging quality. Other important parameters provided by these devices include operation in a stable polarization state, low output power ripple, and linearized wavelength sweeping. This work describes MEMS–VCSEL device design, fabrication, and performance for devices in the 1050nm band relevant to ophthalmic imaging, and the 1310nm band relevant to vascular, skin, and anatomic imaging. Tuning ranges achieved include 100 nm at 1050nm and 150nm at 1310, with the latter result representing the widest tuning range of any MEMS–VCSEL at any wavelength. Both 1050 and 1310nm devices have enabled record imaging speed, record imaging range, and enhanced SS–OCT imaging.