Long-distance vibration measurement based on laser frequency-shifted feedback interferometry

Signal detection of weak vibration in long-distance is of great significance in the fields of machine manufacturing, national defense, military, and so on. Aiming at overcoming the shortages of traditional measurement systems, a long-distance vibration measurement system was built based on the solid-state microchip laser frequency-shifted feedback technology. The system sensitivity index, including working distance, incident angle, and non-cooperative objects were further analyzed. The experimental results show that the high-quality acquisition of the weak vibration signal at 100 m distance is achieved, the frequency measurement error is less than 0.1% and the signal-to-noise ratio is still close to 20 dB under an incident angle of ±60° with using paper box as the target. In addition, the system can measure vibration of a variety of non-cooperative targets such as milk powder bags, polyfoams and so on. The system can be used flexibly in mechanical vibration measurement, remote monitoring and other fields, showing great promotional value in engineering applications.