Silicon-on-sapphire pillar waveguides for Mid-IR supercontinuum generation

Area of Science:

• Photonics and Optical Engineering
• Materials Science
• Nonlinear Optics

Background:

• Silicon photonics typically operates within limited transparency windows due to material absorption.
• Broadband supercontinuum generation is crucial for spectroscopy and optical sensing applications.
• Substrate interaction often limits the performance of silicon-based photonic devices.

Purpose of the Study:

• To propose and analyze pillar integrated silicon waveguides for enhanced optical performance.
• To exploit the full transparency range of silicon (2-6 μm) for nonlinear optics.
• To enable substrate-independent device operation and highly sensitive molecular sensing.

Main Methods:

• Numerical calculation of supercontinuum generation in pillar integrated silicon waveguides.
• Analysis of waveguide dispersion properties, including zero dispersion wavelengths.
• Simulation of mode confinement and interaction with the substrate.

Main Results:

• Demonstrated broad and flat dispersion with four zero dispersion wavelengths (2-6 μm).
• Calculated supercontinuum generation spanning over two octaves (2 to >8 μm).
• Achieved higher mode confinement in silicon, minimizing substrate interaction and loss.

Conclusions:

• Pillar integrated silicon waveguides enable broadband nonlinear optics across silicon's transparency range.
• These structures are substrate independent, enhancing device versatility.
• The proposed waveguides are promising for new nonlinear phenomena and sensitive molecular sensing.