A dynamic acceleration measurement system based on a high sensitivity compliant cylinder fiber optic probe and an all-fiber configuration Distributed Bragg Reflector (DBR) fiber laser with self-mixing technique is presented. The compliant cylinder fiber optic probe consists of a mass-block and an elastic cylinder twined with single mode fiber and can be regarded as being close to that of a simple mass spring system. Experimental results show that the signal to noise ratio (SNR) can achieve 50dB at 800 Hz under 1.5 mg acceleration stimulation, voltage sensitivity is 6.04 V/g and minimum detectable acceleration of the measuring system is 4.7μg/sqrt Hz at 800Hz. Moreover, the material of elastic cylinder is polyurethane (PU) which has better temperature stability and can be applied widely in the field of vibration measurements.
A novel fiber-optic Fabry–Perot accelerometer (FOFPA) based on a spherical air bubble cavity is demonstrated. The cavity is fabricated by corroding a fiber end to form a groove and then arc discharging several times to form a spherical bubble. The bubble diameter and wall thickness are about 130 μm and 5 μm, respectively. Experimental results show that the resonance frequency of the accelerometer is 1520 Hz, the signal to noise ratio (SNR) is 40 dB at 706 Hz under 2 mg acceleration excitation, the voltage sensitivity is 14.16 V/g, and the minimum detectable acceleration of the measuring system is 20 μg/sqrt Hz at 706 Hz. Moreover, the accelerometer has a very low temperature sensitivity of 1.7 pm/°C, which means that FOFPA is basically immune to environmental temperature variation. Thus with advantages of miniaturization and simple structure, the FOFPA can be applied widely in the field of vibration measurements.