Self-mixing flow sensor using a monolithic VCSEL array with parallel readout.

The self-mixing sensing technique is a compact, interferometric sensing technique that can be used for measuring fluid flows. In this work, we demonstrate a parallel readout self-mixing flow velocity sensing system based on a monolithic Vertical-Cavity Surface-Emitting Laser (VCSEL) array. The parallel sensing scheme enables high-resolution full-field imaging systems employing electronic scanning with faster acquisition rates than mechanical scanning systems. The self-mixing signal is acquired from the variation in VCSEL junction voltage, thus markedly reducing the system complexity. The system was validated by measuring velocity distribution of fluid in a custom built diverging-converging planar flow channel. The results obtained agree well with simulation and demonstrate the feasibility of high frame-rate and resolution parallel self-mixing sensors.