Frequency-Stable Nanophotonic Microcavities via Integrated Thermometry
Researchers have developed a method to stabilize the resonance frequency of nanophotonic microcavities by integrating a thin-film resistance thermometer directly above a high-Q silicon nitride (SiN) microresonator. This innovation enables precise local temperature monitoring and active control of the resonator’s wavelength stability.
“Integrating a thin-film resistance thermometer above a high-Q SiN microresonator enables local temperature monitoring and active stabilization of its resonance wavelength.”
The emission wavelength of a distributed feedback laser, when locked to the microresonator, shows remarkable stability, fluctuating within just 0.5 pm over a 50-hour period. This degree of frequency control is crucial for the deployment of integrated photonic systems in demanding environments.
Applications and Significance
- Optical communication and interconnects
- Quantum information processing
- Precision metrology and spectroscopy
- Microwave signal generation
Progress in photonic chip design over the last two decades has greatly expanded their functional complexity. Yet, environmental and electronic thermal disturbances still pose challenges for scalable implementation. The presented approach effectively addresses this limitation.
“Our approach relies on a thin-film metallic resistor placed directly above the microcavity, acting as an integrated resistance thermometer.”
After an initial calibration, the system achieves reliable wavelength control using thermometry alone, maintaining a root-mean-squared wavelength error at an exceptionally low level. This technology offers a path toward stable, field-ready photonic frequency references integrated on silicon platforms.
Author’s Summary
By integrating thermal sensing directly onto photonic microcavities, the study enables high stability and precision in optical frequency control, advancing the practicality of compact photonic systems.