An ultrafast ranging method using optical frequency comb and dispersive Fourier transformation

A dispersive Fourier transformation-based ranging method utilizing a femtosecond laser frequency comb is demonstrated. The target and measurement signals interfere through a Mach-Zehnder interferometer and then enter a single-mode fiber with a sufficiently large group velocity dispersion (GVD) to be stretched and extended. The spectral interference information is mapped to the time-domain waveform. The time-frequency conversion function, obtained through calibration, converts the time-domain data into the frequency-domain data. After applying a Fourier transform, the measured distance is determined using the peak-interval method. In multiple measurements with an interval of 200 μm, the average error is within tens of microns., which can be further reduced with a higher-precision displacement table.