Resolution Enhanced Optical Frequency-Modulated Continuous-Wave Ranging Enabled by Pulse-Tailoring

Fourier transform-limited spatial resolution (TLSR) is regarded as a fundamental limit in optical frequency-modulated continuous-wave (OFMCW) systems. Here, we report on a spatial resolution enhanced ranging method by using a pulse-tailored OFMCW generated by cutting the traditional OFMCW signal with optical pulse trains. Taking advantage of the narrow full-width-at-half-maximum for the auto-correlation of the pulses, a finer spatial resolution can be achieved by scanning the delay of the reference arm while taking the spectral power at the original beat frequencies. The featuring low detection bandwidth inherited from the OFMCW system is preserved. Theories and numerical modelling are firstly provided, and followed by experiments that have efficiently demonstrated a significant improvement of more than 10 times in the achieved spatial resolution compared to the theoretical TLSR in traditional OFMCW systems, even at long distance. Finally, some factors that may affect the measurements have been discussed. The testified spatial resolution enhancement is found quite appealing in various ranging scenarios.