Dispersion engineering of silicon waveguides for enhanced nonlinearities

Abstract

Silicon photonics has gained popularity due to its mature fabrication process and outstanding integration potential, serving as a bridge between photonics and electronics. However, the material’s inherent characteristics pose limitations for light amplification. Nonlinear silicon photonics, particularly through processes such as Raman scattering and four-wave mixing, offers an effective strategy for realising light amplification. Nonetheless, the challenge lies in the relatively small gain associated with each individual nonlinearity. Raman scattering attracted attention as a possible solution to enhance the four-wave mixing effect, offering the prospect of improving gain at Stokes wavelengths. This study delves into the numerical investigation of nonlinear processes in silicon waveguides and silicon core fibres utilising a generalised nonlinear Schrodinger equation. The exploration encompasses Raman scattering, four-wave mixing and Raman-enhanced four-wave mixing in silicon core fibres, with a focus on the telecom band and mid-infrared band. While successful enhancements of conversion efficiency and Stokes output power are achieved, the gains in silicon core fibres are modest due to phase mismatch issues. To address fabrication inaccuracy in silicon core fibres, planar silicon waveguides are employed, advancing in dispersion engineering by precise control of fabricated structure. Coherent Stokes Raman scattering is successfully observed, and the conversion efficiency reaches −30 dB with pump powers of 20 mW and 40 mW in the telecom band and mid-infrared band, respectively. Inspired by the request for wavelength extension via the generation of higher-order Stokes waves, slotted waveguides are investigated as a new promising method for constructing light sources or amplifiers. Slotted waveguides, owning a flat and low dispersion profile, open up avenues for further exploration nonlinear effects in the realm of silicon photonics.

More information

Identifiers

ORCID for Shiyu Sun: orcid.org/0000-0002-8308-2077

ORCID for Goran Mashanovich: orcid.org/0000-0003-2954-5138

ORCID for Anna Peacock: orcid.org/0000-0002-1940-7172

Catalogue record

Export record