Highly sensitive temperature sensor using long period fibre grating

Applications of Optical Fiver Sensor, Glasgow, UK, 22-24 May 2000In this paper, we report a novel technique to increase the temperature sensitivity of a LPG by nearly two hundred times by exploiting the extremely large dependence of the spectral shift of an LPG on its ambient refractive index. The temperature coefficient of the packaged LPG sensor was measured to be 8.8 nm/°C from 16°C to 20°C which is about 180 times higher than an unpackaged LPG. Correspondingly, it is about 800 times more sensitive than a fibre Bragg grating sensor which has a typical temperature coefficient of 0.011 nm/°C.Department of Electrical Engineerin