Localized frequency comb and formation of embedded solitons in silicon-based slot waveguides

TL;DR

This paper investigates the generation of embedded solitons and localized frequency combs in silicon-based slot waveguides using quasi-TM polarized pulses at specific infrared wavelengths, highlighting a novel method for spectral localization.

Contribution

It introduces a new approach to excite embedded solitons in silicon-based waveguides by exploiting specific polarization and wavelength conditions, avoiding Raman effects.

Findings

Spectrally localized continuum observed

Frequency combs generated from embedded solitons

Specific conditions enable soliton excitation in waveguides

Abstract

We explore the possibility to excite the so-called embedded solitons in specially designed slot waveguides based on silicon and silica or silicon nanocrystals. This requires the excitation of the structure with quasi-TM polarized pulses -- for which Raman effect is absent -- and at a specific infrared wavelength for which only the second- and fourth-order group velocity coefficients are non-vanishing. Pulses launched in these conditions will generate a spectrally localized continuum, associated to a frequency comb coming from the spectral interference of many embedded solitons.