Ultrabroad-bandwidth arbitrary radiofrequency waveform generation with a silicon photonic chip-based spectral shaper

Ultrabroad-bandwidth radiofrequency pulses offer significant applications potential, such as increased data transmission rate and multipath tolerance in wireless communications. Such ultrabroad-bandwidth pulses are inherently difficult to generate with chip-based electronics due to limits in digital-to-analog converter technology and high timing jitter. Photonic means of radiofrequency waveform generation, for example, by spectral shaping and frequency–time mapping, can overcome the bandwidth limit in electronic generation. However, previous bulk optic systems for radiofrequency arbitrary waveform generation do not offer the integration advantage of electronics. Here, we report a chip-scale, fully programmable spectral shaper consisting of cascaded multiple-channel microring resonators, on a silicon photonics platform that is compatible with electronic integrated circuit technology. Using such a spectral shaper, we demonstrate the generation of burst radiofrequency waveforms with programmable time-dependent amplitude, frequency and phase profiles, for frequencies up to 60 GHz. Our demonstration suggests potential for chip-scale photonic generation of ultrabroad-bandwidth arbitrary radiofrequency waveforms.