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Published on: July 18, 2015
High reflectivity gratings on silicon-on-insulator waveguide facets
J H Schmid1, P Cheben, J Lapointe
1Institute for Microstructural Sciences, National Research Council Canada, Ottawa, Ontario, Canada. jens.schmid@nrc-cnrc.gc.ca
Optics Express
|October 15, 2008
Summary
Highly reflective facets for silicon waveguides are demonstrated using diffraction gratings. Numerical simulations and experiments show potential for over 90% reflectivity in thicker silicon waveguides.
Area of Science:
- Photonics and optical engineering
- Materials science for optoelectronics
Background:
- Waveguide facets typically have low reflectivity, limiting device performance.
- Diffraction gratings offer a method to enhance optical reflectivity.
Purpose of the Study:
- To demonstrate the formation of highly reflective (HR) facets on silicon waveguides using diffraction gratings.
- To investigate the performance of these HR facets through numerical simulations and experimental validation.
Main Methods:
- Utilizing rigorous coupled wave analysis (RCWA) to design and calculate the performance of high reflectivity diffraction gratings.
- Fabricating silicon-on-insulator (SOI) waveguide facets with grating structures using lithography.
- Employing finite difference time-domain (FDTD) simulations to analyze mode size dependence and predict reflectivity.
Main Results:
- Achieved plane wave reflectivity exceeding 99.99% for the designed HR grating.
- Experimentally demonstrated HR effect on SOI waveguide facets, reaching 77% reflectivity for a 1.5 micrometer thick waveguide.
- FDTD simulations predict modal reflectivities greater than 90% for silicon waveguides with thicknesses of 4 micrometers or more.
Conclusions:
- Highly reflective facets can be successfully fabricated on silicon waveguides using diffraction gratings.
- Waveguide thickness significantly impacts facet reflectivity, with thicker waveguides offering superior performance.
- The demonstrated HR grating technology holds promise for improving optical device efficiency and functionality.
