Optical frequency combs have become a cornerstone of frequency metrology and are now available as commercial systems based on pulsed fiber lasers. Since the Nobel prize in physics was awarded to John L. Hall and Theodor W. Hänsch in 2006, the application space for optical frequency combs has dramatically increased. The use of these combs is currently being studied for the use in ultra-fast acquisition molecular spectroscopy, high-speed and high-accuracy distance ranging (LIDAR) and even for the calibration of instruments in the search of exo-planets. However, the available systems are too bulky and expensive for emerging high-volume applications such as industrial sensing or autonomous driving.

The aim of our project is to develop a chip-based alternative to bulky solid-state and fiber lasers, which are at the heart of current optical frequency combs. The development of photonic integrated circuits, chips with sub-micrometer optical waveguides and components, enabled the creation of on-chip pulsed lasers. However, the performance of the lasers is limited by the currently available photonic technology platforms and are so far unable to seed frequency combs.

In this project, we will develop a photonic technology platform based on the heterogeneous integration of III-V amplifiers on silicon nitride waveguides. Using this new technology, combined with new architectures, we will create integrated mode-locked lasers that can directly seed optical frequency combs.