In-plane microelectromechanical resonator with integrated Fabry–Pérot cavity

A silicon-on-insulator in-plane microelectromechanical resonator coupled to a high-Q (Q≈4,200), high finesse (FMax=265) optical Fabry–Pérot microcavity is presented. The cavity utilizes high reflectance dry-etched silicon/air distributed Bragg reflectors. By suspending one of the Bragg mirrors to a microbridge resonator, the mirror can be displaced and the cavity is tuned. Using electrostatic actuation, bidirectional cavity tuning from −12.1to+17.0nm (29.1nm total range) is demonstrated near 1601nm wavelength. The device also enables measurement of thermal-mechanical noise with sensitivity better than 10fm∕Hz1∕2 and may find application in high resolution sensors.