Scalable ultra-wideband pulse generation based on silicon photonic integrated circuits

We demonstrate a scalable ultra-wideband (UWB) pulse generator using silicon photonic integrated circuits. A delay-and-superimpose principle for higher order UWB Guassian pulse generation is realized by monolithically integrating a pair of tunable microring resonators, a delayline waveguide, tap couplers, and an on-chip photodiode. The two microrings function as discrimination filters and generate the asymmetric monocycle pulses. For a proof-of-concept demonstration, the doublet pulses with a 10-dB fractional bandwidth of 100% and the triplet pulses with a 10-dB fractional bandwidth of 132% are generated by superposition of the two asymmetric pulses with a proper delay between them. The proposed scheme and the photonic chip can be scaled to generate more kinds of powerefficient pulses.