Measurement of Comb Finger and Comb Spacing Stability in Phononic Frequency Comb

In this paper, we present a method for measuring the frequency stability of each comb finger and comb spacing in a phononic frequency comb. Based on this method, we present the experimental results of the stability of the comb fingers and comb spacing in a piezoelectrically actuated free-free beam microstructure for the first time. The theoretical and experimental results show that the Allan deviation of the comb finger increases approximately linearly with the increase of the comb order, while the Allan deviation of comb spacing is independent of comb order. These results provide a reference for the application of frequency comb and are expected to accelerate its application.