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Fabrication And Characterization Of Photonic Crystal Slow Light Waveguides And Cavities
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Low-loss optical waveguides made with a high-loss material.
Darius Urbonas1, Rainer F Mahrt1, Thilo Stöferle2
1IBM Research Europe-Zurich, Säumerstrasse 4, 8803, Rüschlikon, Switzerland.
Light, Science & Applications
|January 13, 2021
Summary
Subwavelength gratings enable broadband, multimode waveguides with low propagation loss, even with highly absorbing materials like silicon. This breakthrough overcomes limitations in silicon photonics for visible light guiding.
Area of Science:
- Photonics
- Materials Science
- Nanotechnology
Background:
- Guiding light on-chip traditionally requires materials with low absorption and scattering.
- Subwavelength gratings offer a novel approach to waveguide design.
Discussion:
- Rigorous coupled-wave analysis and finite-difference time-domain simulations were used to design and analyze the waveguides.
- The proposed waveguides utilize pairs of integrated high-index-contrast gratings.
Key Insights:
- Demonstrated broadband, multimode waveguides with propagation losses as low as 6 dB/cm for visible light (550-650 nm).
- Achieved low loss despite using silicon gratings with a material absorption of 13,000 dB/cm.
- Successfully guided visible light using standard silicon photonics technology.
Outlook:
- This technology overcomes spectral range limitations of existing photonics platforms.
- Enables the use of intrinsically absorbing materials (e.g., doped semiconductors) essential for active photonic devices like amplifiers, lasers, and modulators.
