Ultrafast lasers are light sources that generate intense and coherent ultrashort optical pulses on picosecond and femtosecond timescales. Despite being a workhorse in laboratory experiments for fundamental studies, many ultrafast light sources, such as mode-locked lasers, remain impractical for daily use due to their bulky size, high cost, and substantial power consumption. The transformation of table-top ultrafast photonic systems into compact, chip-scale platforms holds the potential to unlock a myriad of exciting new applications, such as on-chip photonic coherent computing, quantum sensing, and portable imaging tools for healthcare.

A major hurdle that impedes the realization of chip-scale ultrafast photonic systems is the absence of energy-efficient and reconfigurable optical nonlinearity, which is crucial for optical pulse formation, wavelength conversion, information processing, and frequency stabilization. We aim to tackle this outstanding challenge by leveraging emerging integrated photonic platforms with strong and reconfigurable quadratic optical nonlinearity, with the ultimate goal of developing highly efficient, reconfigurable on-chip ultrafast photonic systems. We will also harness the exotic nonlinear optical phenomena to enable new capabilities in quantum sensing and ultrafast all-optical information processing, which are beyond reach by conventional methods.