Fabrication and Test of Novel Fiber Bragg Grating Based Humidity Sensor

Optical humidity measurement is essential in current industry, especially in environment with adverse electromagnetic field and strong corrosion. This paper focus on the fabrication and test of a novel fiber bragg grating based humidity sensor. The sensor is fabricated by uniformly coating humidity sensitive material on fiber bragg grating. The sensing characteristic test of the sensor shows: the wavelength shift following humidity is linear; the minimum response time of the 2-layer coated sensor is 10 s with sensitive coefficient can be controlled by changing coating time; hygroscopic hysteresis of 3-layer coated sensor is 2.7`% RH. Therefore, the sensor is promising to be used to meet the quick response and in vivo measurement demand in industry.