  Optical ranging is a key technology in metrology. Optical frequency combs are
shown to provide several advantages in light ranging, offering high precision
with high acquisition rate. However, performance of traditional ranging systems
based on microcombs is limited by the short ambiguity distance and
non-real-time processing. Here, we show that dual-comb ranging system using
coherent Kerr soliton microcombs and optical switch realizes extended ambiguity
distance and provides a route to real-time processing. The ambguity distance is
extended to 3.28 m from about 1.5 mm and the uncertainty reaches about 1.05
times 10^-7, while the system is compatible with low-bandwidth detectors.
Combining coherent microcomb ranging systems with special FPGA could enable
comb-based real-time ranging systems for several applications such as
industrial process monitoring.
