High-Resolution FMCW Reflectometry Using a Single-Mode Vertical-Cavity Surface-Emitting Laser

High-resolution frequency-modulated continuous-wave (FMCW) reflectometry is realized by using a single-mode vertical-cavity surface-emitting laser (VCSEL) as a frequency-swept light source for the first time. The optical frequency of the VCSEL is swept by the injection current modulation. The experimental spatial resolution of 250 μm was achieved, which is the best value when an injection current tuned laser diode is used as a frequency-swept light source.