Fig. 1. Schematic diagram and principle of FMCW signal analysis

Fig. 2. Blue light external cavity semiconductor laser

Fig. 3. Comparison of the optical spectrum and the interference signal of the diode laser with and without external feedback

Fig. 4. Schematic diagram of ranging system

Fig. 5. FFT spectrum comparison before and after resampling

Fig. 6. FMCW ranging results

Fig. 7. Relationship between actual distance and measured distance

Fig. 8. Distance measurement error