Temperature-independent accelerometer using a fiber Bragg grating incorporating a biconical taper

• A fiber-optic accelerometer by using a FBG incorporating a biconical taper is proposed.
• The accelerometer achieves a high sensitivity of 4.85 nW/g with the static range of 5g.
• Vibration measurement has been achieved with the resonant frequency of 20 Hz.
• The accelerometer reduces the cost and complexity of the sensor setup.

An intensity-modulated optical fiber accelerometer is proposed and experimentally demonstrated by using a fiber Bragg grating (FBG) incorporating a biconical fiber taper. Acceleration-induced microbending of the fiber taper region introduces various attenuation to the light, so that acceleration can be measured from changes of the optical power of the reflected light from the FBG. This power detection method reduces the cost and complexity of the sensor setup since only photodetector is required for the signal detection. In the static measurement, a relatively large range of 5g (g is gravity, equals to 9.8 m/s2) with sensitivity of 4.85 nW/g is achieved. Vibration measurements have also been carried out with a frequency up to 20 Hz. The proposed accelerometer is nearly independent of temperature because the reflected optical power of the FBG is insensitive to temperature.