High-sensitivity sensing of force is realized through an all-fiber cavity ring-down structure. Based on a fiber coupler with a coupling ratio of 99:1, instead of a traditional ring-down cavity mirror, an all-fiber ring-shaped decay cavity was designed and manufactured. This experiment uses a continuously tunable narrow linewidth laser for wavelength scanning, and uses an FBG with a center wavelength of 1550 nm for wavelength filtering in the scanning process. A zigzag micro-bend modulation module with a period of 2mm is designed, the fiber in the cavity passes through the module twice, and the length of the sensing area is 8 cm. The detection sensitivity corresponding to the pressure of 8~16N measured at room temperature is 0.07722μs -1·N-1 . The results show that the fiber cavity ring-down structure based on the whole fiber has high sensitivity and a good application prospect in the field of real-time pressure monitoring.
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