A Yale Engineering team led by Prof. Peter Rakich has adapted the classic Fabry–Pérot resonator for use in photonic integrated circuits. Traditionally used in high-end optics and atomic clocks, these resonators trap light between two mirrors to achieve extremely stable frequency references. The team introduced “reflection transformation circuits” that enable the resonator to tune itself to match the frequency of an on-chip laser. This tuning leads to self-injection locking, where the laser effectively inherits the low-noise, high-stability properties of the resonator—without the need for vacuum systems or bulky setups.
This breakthrough enables chip-scale lasers with ultra-low frequency noise, opening the door to high-precision applications in communication, sensing, LiDAR, and quantum networks. The researchers aim to integrate this technology into systems for fiber-optic seismic sensing and low-noise microwave oscillators, with potential impact across navigation, radar, and fundamental physics. The work was published in Nature Photonics and represents a major step toward compact, high-performance photonic devices for the quantum age. Read more here.