Tapered Fiber Attached Nitrile Diaphragm-Based Acoustic Sensor

We present a low-cost acoustic sensor using tapered fiber structure attached to a nitrile polymer-based diaphragm. The tapered fiber is attached in the line of symmetry of a circular diaphragm of optimized thickness and diameter. The applied acoustic pressure deforms the diaphragm, which bends the tapered fiber attached with it. The bending induced change in transmission power is utilized to detect the applied acoustic pressure. The acoustic sensitivity and minimum detectable pressure at 2500 Hz are 36 mV/kPa and 21.11 Pa/√Hz, respectively, for the sensor setup with tapered fiber waist diameter of 18.37 μm. The sensor shows a reasonably flat response from 250 to 2500 Hz. The performance parameters of the sensor, such as sensitivity, minimum detectable pressure, and flat response range can be easily tailored by changing the dimensions of diaphragm and tapered fiber.