Vernier microcombs for high-frequency carrier envelope offset and repetition rate detection
Kaiyi Wu, Nathan P. O’Malley, Saleha Fatema, Cong Wang, Marcello Girardi, Mohammed S. Alshaykh, Zhichao Ye, Daniel E. Leaird, Minghao Qi, Andrew M. Weiner
Abstract
Recent developments in Kerr microcombs may pave the way to a future with fully stabilized ultralow size, weight, and power consumption (SWaP) frequency combs. Nevertheless, Kerr microcombs are still hindered by a bandwidth/repetition rate trade-off. That is, the octave bandwidth needed for self-referencing is typically realized only with ∼THz repetition rates beyond the range of standard commercial photodetectors. The carrier envelope offset frequency is often likewise too high for detection. Dual-comb techniques for the measurement of THz repetition rates have made exciting progress, but the f CEO detection problem remains largely unaddressed. In this work, utilizing a Vernier dual-comb configuration, we demonstrate simultaneous detection of the electronically divided repetition rate and f CEO carrier envelope offset frequency of an octave-spanning microcomb. This, in turn, could help usher optical atomic clocks, low-noise microwave generators, and optical frequency synthesizers into various real-world applications.