Ultrahigh bandwidth signal processing and artificial intelligent computing with integrated Kerr microcombs

Microwave photonic (MWP) transversal signal processors offer an attractive solution for versatile high-speed information processing by combining the advantages of reconfigurable electrical digital signal processing and high-bandwidth photonic processing. With the capability of generating a number of discrete wavelengths from micro-scale resonators, optical microcombs are powerful multi-wavelength sources for implementing MWP transversal signal processors with significantly reduced size, power consumption, and complexity. By using microcomb-based MWP transversal signal processors, a diverse range of signal processing functions have been demonstrated recently. Here, we present a detailed analysis for the processing inaccuracy that are induced by the imperfect response of experimental components. We investigate the errors arising from different sources including imperfections in the microcombs, electro-optic modulator chirp, chromatic dispersion of the dispersive module, shaping errors of the optical spectral shapers, and noise of the photodetector. Next, we provide a global picture quantifying the impact of different error sources on the overall system performance. Finally, we introduce feedback control to compensate the errors caused by experimental imperfections and achieve significantly improved accuracy. These results provide a guide for optimizing the accuracy of microcomb-based MWP transversal signal processors.