In this work, a beat-frequency encoded fiber laser hydrophone is developed for\nhigh-resolution acoustic detection by using an elastic corrugated diaphragm. The diaphragm\nis center-supported by the fiber. Incident acoustic waves deform the diaphragm and induce a\nconcentrated lateral load on the laser cavity. The acoustically induced perturbation changes local\noptical phases and frequency-modulates the radio-frequency beat signal between two orthogonal\nlasing modes of the cavity. Theoretical analysis reveals that a higher corrugation-depth/thickness\nratio or larger diaphragm area can provide higher transduction efficiency. The experimentally\nachieved average sensitivity in beat-frequency variation is 185.7 kHz/Pa over a bandwidth of\n1 kHz. The detection capability can be enhanced by shortening the cavity length to enhance the\nsignal-to-noise ratio. The minimum detectable acoustic pressure reaches 74 �¼Pa/Hz1/2 at 1 kHz,\nwhich is comparable to the zeroth order sea noise.
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