Liquid-level sensor using a fiber Bragg grating and carbon fiber composite diaphragm

A novel liquid-level sensor based on a fiber Bragg grating and carbon fiber composite diaphragm is proposed and demonstrated. The sensing principle and finite element analysis result are described. Because the carbon fiber composite diaphragm's thickness is 0.2 mm and thinner than that of other materials, the sensitivity of the liquid-level sensor is improved. The experimental results show that sensitivity can reach 0.185 nm/m of water height. Based on the high sensitivity and the simple structure of the sensor, this sensor can find applications in the area of liquid level sensing. (C) 2011 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI: 10.1117/1.3525286]