Real-Time Experimental Measurement of Swept Source VCSEL Properties Relevant to OCT Imaging

A real-time study of the dynamic properties of a frequency swept vertical cavity surface emitting laser (VCSEL) is presented. Such tunable laser sources have previously been shown to provide long coherence lengths and improved performance in metrology and imaging applications. Single-shot interferometric reconstruction of both the phase and intensity of the swept source allows for experimental measurement of the full complex electric field over multiple sweep periods. Access to the electric field enables direct measurement of laser properties that can be related to the imaging performance of the laser when used in a swept source optical coherence tomography application. Both inter-sweep and intra-sweep characterization is possible, including determination of the instantaneous spectral shape, sweep rate, linewidth, coherence roll-off, and point spread function.