All Fiber-Optic Sensor for Monitoring Pressure Fluctuations in ON/OFF State

We report a simple, cost-efficient fiber-optic sensor for monitoring pressure fluctuations in ON/OFF state. The working principle of the proposed sensor is based on light intensity modulation of a reflected signal when external pressure fluctuations cause coupling optical signal variation between two multimode optical fibers placed side by side in front of a plane reflecting mirror attached on a pressure-sensitive diaphragm. The proposed sensing technique is found to be suitable for monitoring both periodic and nonperiodic forms of pressure variations in ON/OFF state. With our proposed sensor design, pressure variation as small as 1.5×10^-5 N/cm² can be measured with accuracy and repeatability.