Multiplexing optical fiber-based pressure sensors for smart wings

A novel, multiplexed optical fiber differential-pressure transducer is described for the realtime pressure measurement of airflow in applications involving actuator-and SMA-controlled airfoils and multi-parameter skin friction measurements. The design of the pressure transducer is based upon extrinsic Fabry-Perot interferometry (EFPI) and uses a micromachined silicon diaphragm to modulate the sensing cavity. The pressure transducer was designed to operate from -10 to 10 psi(g) and have a resolution of greater than 0.01 psi. Ten pressure transducers were spatially multiplexed and tested for smart wing applications. Results are also reported for an integrated skin friction balance/optical fiber pressure transducer tested in Virginia Tech's Supersonic Tunnel (VTSST).