Kerr-Nonlinearity-Induced Mode-Splitting in Optical Microresonators

Area of Science:

• Photonics
• Nonlinear Optics
• Quantum Optics

Background:

• The Kerr effect in optical microresonators is fundamental for integrated photonic devices.
• It enables phenomena like third harmonic generation, four-wave mixing, and frequency comb generation.
• Understanding and controlling nonlinear effects in microresonators is key for advanced optical functionalities.

Purpose of the Study:

• To experimentally demonstrate and characterize Kerr nonlinearity-induced resonance splitting in ultra-high-Q microresonators.
• To investigate the use of self- and cross-phase modulation for splitting resonances.
• To explore applications of controlled resonance splitting in photonic devices.

Main Methods:

• Utilizing a pump-probe spectroscopy scheme.
• Employing two continuous-wave lasers to induce and probe resonance splitting.
• Measuring power-dependent resonance splittings in ultra-high-Q microresonators.

Main Results:

• Demonstrated Kerr nonlinearity splitting of microresonator resonances for two continuous-wave lasers.
• Observed resonance splittings up to 35 cavity linewidths (52 MHz) at 10 mW pump power.
• Achieved resonance splitting by one cavity linewidth with only 286 μW of pump power.
• Showcased threefold resonance splitting considering four-wave mixing and counterpropagating probe lasers.

Conclusions:

• Kerr nonlinearity enables precise optical control over microresonator mode splitting.
• The demonstrated effect allows simultaneous resonance of two lasers in a single mode, counterintuitively.
• These Kerr splittings offer potential for applications in optomechanics, optical memories, and tunable spectral filters.