Fig. 1. Principle of displacement measurement using fiber Fabry-Pérot interferometer

Fig. 2. Fiber Fabry-Pérot interferometer experimental setup

Fig. 3. (a) Forward tilt, (b) reverse tilt process Linear fitting results of the steps and the readings of the photoelectric auto-collimator

Fig. 4. Optical path diagram for the configuration of collimating lens and low-reflectance mirror

Fig. 5. Relationship between contrast and the reflection surface tilt angle α at WD = 30 mm

Fig. 6. Optical path diagram for the collimating lens and high-reflectivity mirror configuration. (a) Overall optical path diagram; (b) Optical path diagram near the fiber end face

Fig. 7. Experimental and simulation diagrams of the configuration with a collimating lens and a high-reflectance plane. (a) The relationship between I_max, I_min and tilt angle α of the reflective surface; (b) The relationship between contrast and tilt angle α of the reflective surface; (c) The relationship between I_max, I_min and WD; (d) The relationship between contrast and WD

Fig. 8. Simulated interference fringes and actual interference fringes in overlapping state

Fig. 9. Optical path diagram for the configuration of focusing lens and low-reflectance mirror

Fig. 10. Experimental and simulation diagrams of the configuration with a focusing lens and a low-reflectance plane. (a) The relationship between I_max, I_min and tilt angle α of the reflective surface; (b) The relationship between contrast and tilt angle α of the reflective surface; (c) The relationship between I_max, I_min and WD; (d) The relationship between contrast and WD

Fig. 11. Optical path diagram for the configuration of focusing lens and high-reflectance mirror

Fig. 12. Experimental and simulation diagrams of the configuration with a focusing lens and a high-reflectance plane. （a) The relationship between I_max, I_min and tilt angle α of the reflective surface; (b) The relationship between contrast and tilt angle α of the reflective surface; (c) The relationship between I_max, I_min and WD; (d) The relationship between contrast and WD

Fig. 13. The relationship between contrast and tilt angle α for target reflectors with different reflectance under (a) collimation mode and (b) focusing mode