High performance chitosan diaphragm-based fiber-optic acoustic sensor

A miniature fiber-optic Fabry–Perot is fabricated directly on the tip of a single mode fiber. The active sensing element is a thin linear polysaccharide (chitosan) diaphragm with thickness of only 1.5 μm. The chitosan diaphragm exhibits excellent physicochemical properties that include membrane-forming ability, good adhesion, insensitive to background pressure and high mechanical strength. Together with fiber-optic Fabry–Perot interferometric's inherent advantages, the chitosan diaphragm-based Fabry–Perot sensor becomes a wonderful candidate for dynamic pressure measurement such as acoustic pressure. A chitosan diaphragm-based miniature Fabry–Perot system for acoustic pressure measurement is presented which exhibits high sensitivity of 0.002 V/mPa at 1 kHz with frequency response from range 20 Hz to 20 kHz.