Nanowerk March 19, 2024
Current implementations of optical frequency division (OFD) require multiple lasers, with space- and energy-consuming optical stabilization and electronic feedback components, resulting in device footprints incompatible with integration into a compact and robust photonic platform. A team of researchers in the US (industry, Columbia University) demonstrated all-optical OFD on a photonic chip by synchronizing two distinct dynamical states of Kerr microresonators pumped by a single continuous-wave laser. The inherent stability of the terahertz beat frequency was transferred to a microwave frequency of a Kerr soliton comb, and synchronized via a coupling waveguide without the need for electronic locking. OFD enabled a 46 dB phase-noise reduction for the 16 GHz soliton comb, resulting in the lowest microwave noise observed in an integrated photonics platform. According to the researchers their approach provides a pathway towards chip-scale devices that can generate microwave frequencies comparable to the purest tones produced in metrological laboratories… read more. TECHNICAL ARTICLE
Schematic of on-chip low-noise microwave generation via frequency division. Credit: Nature, 11 March 2024