Inter-mode soliton linear-wave scattering in a Kerr microresonator

Area of Science:

• Nonlinear Optics
• Integrated Photonics
• Optical Frequency Combs

Background:

• Soliton microresonator frequency combs (microcombs) are promising optical sources with diverse applications.
• Extending the optical bandwidth of microcombs is crucial for enhanced functionality.
• Previous work explored injecting a probe wave to generate new frequencies via nonlinear scattering.

Purpose of the Study:

• To analyze soliton-linear wave interactions when soliton and probe fields occupy different mode families.
• To derive an expression for phase-matched idler locations based on resonator dispersion and probe detuning.
• To experimentally validate theoretical predictions in a silica waveguide ring microresonator.

Main Methods:

• Theoretical analysis of nonlinear scattering and four-wave mixing processes.
• Derivation of phase-matching conditions for intermodal interactions.
• Experimental implementation using a silica waveguide ring microresonator and an injected optical probe wave.

Main Results:

• An expression for phase-matched idler locations was obtained, dependent on resonator dispersion and probe phase detuning.
• The study successfully analyzed soliton-linear wave interactions across different mode families.
• Experimental results confirmed the theoretical predictions for generating new comb frequencies.

Conclusions:

• The interaction between solitons and probe waves in different modes is a viable method for bandwidth extension.
• The derived formula accurately predicts the locations of generated frequencies.
• This research advances the development of broadband optical microcombs for various applications.