Suspended mid-infrared waveguides for Stimulated Brillouin Scattering

Area of Science:

• Photonics and optical engineering
• Materials science
• Acoustics

Background:

• Stimulated Brillouin Scattering (SBS) is crucial for optical signal processing.
• Existing mid-infrared (MIR) SBS devices face challenges with acoustic confinement and loss.
• Silicon photonics offers a promising platform for integrated optical devices.

Purpose of the Study:

• To theoretically investigate a new class of silicon waveguides for enhanced SBS in the MIR.
• To design a waveguide structure that minimizes acoustic radiative losses.
• To achieve high SBS gain coefficients in a compact silicon platform.

Main Methods:

• Theoretical modeling of opto-acoustic interaction in periodic structures.
• Design of a silicon waveguide with a phononic crystal for acoustic wave confinement.
• Calculation of Stimulated Brillouin Scattering (SBS) gains.

Main Results:

• Forward intramodal-SBS gains up to 1750 m^-1W^-1 were predicted.
• The proposed design significantly suppresses acoustic radiative losses.
• Performance favorably compares with existing mid-infrared SBS waveguide designs.

Conclusions:

• The novel silicon waveguide design enables highly efficient SBS in the mid-infrared.
• Effective acoustic wave confinement via phononic crystals is key to achieving large gains.
• This work paves the way for advanced MIR photonic devices based on silicon.