Tunable sensitivity from low to high by spring tension in acoustic detection system containing weak grating fiber

The tunable sensitivity from low to high by spring tension in an acoustic detection system containing weak grating fiber is demonstrated for the first time. The noise power spectrum and minimum detection strain sensitivity of the surface wound sensing fiber of the spring-sensitized structure in air can be obtained with the value of -77.2 dB rad/Hz and 3.5 pε/√Hz, respectively. The strain sensitivity of the acoustic detection system can reach at about 1 by adjusting the amount of compression of the spring in sensitized structure. The effective detection and high-fidelity restoration of music in the air further show that the acoustic detection system containing weak grating fiber based on adjustable spring sensitization can be used for the accurate detection of weak signals underground, especially in the refined exploration of downhole oil and gas reservoirs.