Passively mode-locked multi-longitudinal mode fiber laser sensor for acoustic pressure measurement

We proposed a fiber laser sensor (FLS) based on passively mode-locked. A polymer membrane is used beneath the pre-strained EDF to convert the sound pressure disturbance into axial strain, then alter the cavity length. Hence acoustic pressure measurement can be carried on by detecting the shift of beat frequency. Experiment results show comparable sound pressure sensitivity 147.2Hz/Pa. The proposed sensor provides an alternative way to detect acoustic pressure and has advantages of good stability and easy to interrogate.