Fast High-Resolution Measurement of an Arbitrary Optical Pulse Using Dual-Comb Spectroscopy

Abstract

We present amplitude and phase characterization of short optical pulses using dual-comb spectroscopy, where one comb is a well-characterized stable-frequency comb and the second is the pulse source to be measured. We demonstrate that the technique is suitable for truly arbitrary repetition rates of the two combs. Moreover, the system is highly sensitive and is shown to enable measurements of low-intensity pulses. In one experiment we use relatively long (80-ps) pulses generated by an actively mode-locked semiconductor laser at a repetition rate that is slightly different from that of the reference laser. In a second experiment, we employ 2-ps pulses generated by a fiber laser whose repetition rate differs significantly from that of the reference laser. We benchmark the method by comparison with conventional methods of pulse characterization. Furthermore, limitations due to fluctuations of the carrier-envelope offset and the repetition rate, are addressed and overcome by implementing computational nonuniform sampling of measured interferograms.