Temperature-insensitive fiber Bragg grating tilt sensor
A temperature-insensitive optical fiber tilt sensor is presented. The sensor scheme uses a prestrained fiber Bragg grating to sense the strain, which depends on the tilt angle. To compensate for the temperature effect, materials that have different linear thermal expansion behaviors are used for implementation of the sensor body. The differentiation in the linear thermal expansion would then cause a counter effect to the original temperature effect. Experimental tests show an accuracy of ±0.167° in tilt angle measurement. A temperature stability better than ±0.33° over the temperature range from 27 °C to 75 °C is demonstrated. The resolution 0.0067° in tilt angle measurement is achieved by using our preliminary sensor with a dimension of 16×5×5 cm3.