Mechanical Kerr nonlinearities due to bipolar optical forces between deformable silicon waveguides

Area of Science:

• Optics and Photonics
• Materials Science
• Nanotechnology

Background:

• Optical forces arise from light-matter interactions.
• The mechanical Kerr effect describes light-induced changes in material's mechanical properties.
• Coupled waveguide systems are crucial for integrated photonics.

Purpose of the Study:

• To investigate the mechanical Kerr effect in coupled silicon waveguides.
• To analyze the influence of optical forces on the mechanical Kerr effect.
• To explore methods for enhancing the mechanical Kerr coefficient.

Main Methods:

• An analytical method based on effective index perturbation at fixed frequency was employed.
• Optical forces between silicon waveguides were calculated.
• The mechanical Kerr effect in a coupled-waveguide system with bipolar forces was investigated.

Main Results:

• A positive mechanical Kerr coefficient was observed for both attractive and repulsive optical forces.
• An enhanced mechanical Kerr coefficient, orders of magnitude larger than the intrinsic value, was achieved.
• This enhancement is significant in waveguides where the optical mode approaches the air light line.

Conclusions:

• Optical forces play a critical role in the mechanical Kerr effect in silicon waveguides.
• Waveguide design, particularly approaching the air light line, can dramatically enhance the mechanical Kerr coefficient.
• This finding has implications for designing novel optomechanical devices.