Mid-Infrared Soliton and Raman Frequency Comb Generation in Silicon Microrings

TL;DR

This paper investigates how silicon microring resonators can generate mid-infrared frequency combs, including soliton and Raman types, by controlling free-carrier effects and nonlinear detuning, with numerical simulations guiding the process.

Contribution

It introduces a method to achieve coherent soliton combs at zero linear detuning by managing free-carrier lifetime, advancing mid-infrared comb generation in silicon microrings.

Findings

Coherent soliton combs are achievable at zero linear detuning.

Optimal conditions for octave-spanning Raman combs are identified.

Free-carrier dispersion enables nonlinear cavity detuning control.

Abstract

We numerically study the mechanisms of frequency comb generation in the mid-infrared spectral region from cw pumped silicon microring resonators. Coherent soliton comb generation may be obtained even for a pump with zero linear cavity detuning, through suitable control of the effective lifetime of free-carriers from multiphoton absorption, which introduces a nonlinear cavity detuning via free-carrier dispersion. Conditions for optimal octave spanning Raman comb generation are also described.