1：Experimental Design and Method Selection:

The study involved designing a vibration sensor using a Fabry-Perot interferometer (FPI) with an in-fiber collimator to enhance sensitivity. Theoretical models for divergence angle, displacement response, and natural frequency were employed.

2：Sample Selection and Data Sources:

The sensor was fabricated using specific fibers: quarter-pitch graded index fiber (GIF), hollow-core fiber (HCF), and single mode fibers (SMFs). Data were collected from static displacement and dynamic vibration experiments.

3：List of Experimental Equipment and Materials:

Equipment included a tunable laser, fusion splicer, fiber cleaving system, optical microscope, photodiode, piezoelectric transducer, transimpedance amplifier, data acquisition board, and personal computer. Materials included GIF, HCF, SMFs, and a 1×2 3-dB coupler.

4：Experimental Procedures and Operational Workflow:

The sensor fabrication involved splicing and cleaving fibers to create the FPI structure. Static displacement was measured by moving a fulcrum bar and monitoring spectra, while vibration response was tested using a vibration generator and recording signals.

5：Data Analysis Methods:

Data were analyzed using fast Fourier transform (FFT) for frequency domain analysis, and sensitivity was calculated from linear fits of displacement and acceleration responses.