MEMS Optical Fiber F–P Hydrophone Based on Corrugated PET Diaphragm

In this article, a micro-electro-mechanical system (MEMS) optical fiber Fabry–Perot (F–P) hydrophone based on corrugated polyethylene terephthalate (PET) diaphragms was proposed, fabricated, and measured. Corrugations of different depths were introduced into the PET by simple hot-embossing process. The optical parameters and acoustic characteristics of the fabricated hydrophones were measured and analyzed. In order to maintain a balanced pressure difference between the inside and outside of the F–P cavity, a microflow path structure is designed as a connecting vent and maintains an air cavity, which could improve the sensitivity. Using corrugated PET diaphragms as an acoustic pressure sensitive module of the hydrophones could reduce manufacturing cost, and the measurement results showed that the corrugations could effectively improve the performances of the hydrophones.