Basic study on real-time vibration displacement measurement using probe light modulated by phase-modulated RF signal

We propose real-time vibration displacement measurement system using probe light modulated by phase-modulated RF signal. The reflected probe light is processed by a signal detection unit composed of an optical intensity modulator and lock-in amplifier. Proof-of-concept experiment demonstrates real-time measurement of 50-Hz vibration displacement with an amplitude of 21 mm.