Simple Approach for Ambiguity-Free Dual-Comb Ranging Using an Intrinsically Modulated Single-Cavity Laser Source

Since the first demonstration of high-precision distance measurements based on two optical frequency combs [1] , simplifying the measurement scheme has been an ongoing effort. Compared to established time-off-light techniques, the precision of dual-comb-ranging (DC-R) is increased by a scaling factor f rep,2 /Δ f rep ; where f rep,2 is the repetition rate of the comb used for the distance measurement, and Δ f rep is the difference in repetition rates between the two combs, i.e. | f rep,1 - f rep,2 |. However, for state-of-the-art DC-R, two phase-stable combs are needed and the measurement becomes ambiguous if the distance L is longer than c/ f rep , which is typically a few meters only [1] . It has been demonstrated that by using a single-cavity dual-comb, the complexity of the measurement setup can be decreased [2] , [3] . However, the short non-ambiguity range is still a problem limiting the applications of DC-R. Different methods have been presented to extend the non-ambiguity range [2] , [3] , e.g. by using the Vernier effect or by introducing an additional reference arm, which however increases the complexity of the measurement.