Optical frequency comb generation from a monolithic microresonator

Area of Science:

• Photonics and Quantum Optics
• Nonlinear Optics
• Metrology

Background:

• Optical frequency combs are crucial for high-precision frequency measurements, linking optical to radio frequencies.
• Traditional methods, like mode-locked lasers, are complex and bulky.
• Novel approaches are needed for miniaturized and efficient comb generation.

Purpose of the Study:

• To demonstrate a new method for generating optical frequency combs using microresonators.
• To achieve broadband comb generation with high mode spacing uniformity.
• To explore a more compact and power-efficient comb generation technique.

Main Methods:

• Utilizing the Kerr nonlinearity in a monolithic ultra-high-Q microresonator.
• Interacting a continuous-wave pump laser with microresonator modes.
• Employing optical-heterodyne measurements to characterize comb properties.

Main Results:

• Generated an optical frequency comb with a 500-nm bandwidth around 1,550 nm.
• Achieved mode spacing uniformity with a relative precision of 7.3 x 10⁻¹⁸.
• Demonstrated cascaded parametric interactions overcoming passive cavity dispersion.

Conclusions:

• This microresonator-based approach offers a path towards monolithic optical frequency comb generators.
• The method significantly reduces size, complexity, and power consumption compared to existing technologies.
• Enables operation at high repetition rates (>100 GHz) for advanced applications.