Surface Acoustic Wave Detection System Based on Acousto-Optic Effect of On-Chip Microfiber

An on-chip acousto-optic detection system based on surface acoustic wave (SAW) modulated microfiber is proposed and experimentally verified. Part of the SAW energy is coupled to the microfiber by acoustic couplant, forming in-fiber acousto-optic phase modulation. The constructed acousto-optic detection system is utilized to measure the amplitude-frequency response of an interdigital transducer (IDT) with a center frequency of 29.4 MHz, and the measured results are in agreement with the simulation results and electrical measurements. Based on demodulation of the acousto-optic modulation phase, the system can further measure time domain signal of SAW devices and be used for microwave signal transmission. The proposed acousto-optic measurement system gains compatibility of on-chip and all-fiber systems, and has the potential to be developed as a miniaturized, high-sensitivity and wideband SAW detection system for applications in micro-electro-mechanical system (MEMS) sensing, SAW device characterization and microwave transmission.