Fig. 1. Angular frequency relationship between interference wave and beat signal in FMCW laser interference

Fig. 2. Optical fiber FMCW laser interferometer displacement measurement system block diagram

Fig. 3. Schematic diagram of optical interference system structure

Fig. 4. Frequency modulated continuous wave laser interferometric schematic diagram of displacement measurement system

Fig. 5. Overall block diagram of signal processing circuit

Fig. 6. Fixed wavelength experimental setup diagram

Fig. 7. Experimental measurement results of cavity length fluctuations. (a) Random error of cavity length fluctuation;(b) histogram of random error of cavity length fluctuation

Fig. 8. Experimental device diagram of optical fiber FMCW interference displacement measurement

Fig. 9. Scatter plots and distribution plots of the measurement results of fixed point targets at different locations. (a)(c)(e) Scatter plots of measurement results at 200 mm, 400 mm, and 600 mm, respectively; (b)(d)(f) distribution plots of measurement results at 200 mm, 400 mm, and 600 mm, respectively

Fig. 10. Standard deviation distribution of measurement results of fixed point targets at different locations

Fig. 11. Linearity measurement results of the moving target under sawtooth wave modulation. (a) Measurement result of 200‒400 mm; (b) measurement result of 0‒600 mm

Fig. 12. Repeatability measurement experiment diagram. (a) Four repeated measurement results of 200‒400 mm;(b) four repeated measurement results of 0‒600 mm

Table 1. Displacement measurement results at different movement speeds