Silicon-on-sapphire ring resonators operate at a 5.5 μm wavelength

Feb. 1, 2011
Researchers at the University of Washington and Cornell University have created the first silicon-waveguide ring resonators for wavelengths between 5.4 and 5.6 μm.

Researchers at the University of Washington (Seattle, WA) and Cornell University (Ithaca, NY) have created the first silicon-waveguide ring resonators for wavelengths between 5.4 and 5.6 μm, opening up a new region for ring-resonator applications such as biosensing and modulation. The resonators, as well as ridge waveguides, were fabricated on a silicon-on-sapphire (SOS) substrate.

The chip was patterned using electron-beam lithography and contained various ridge waveguides and ring resonators. Waveguides with a height of 0.6 μm and varying widths were fabricated; as predicted, a 1.8 μm wide waveguide properly channeled the fundamental mode of linearly polarized light at a 5.5 μm wavelength. The measured loss of the ridge waveguide was 4.0 ± 0.7 dB/cm at laser powers ranging from 6 to 100 mW (with an insertion loss of 25 dB), indicating minimal nonlinear loss. The ring resonators had various radii and edge-to-edge spacings; a sample ring had a 40 μm radius and a 0.25 μm edge-to-edge spacing, and exhibited a cavity Q factor of 3000, a free spectral range of 29.7 nm, and an associated group index of 3.99. Optimizing the drop port should boost the Q closer to its theoretical value of 25,000. Contact Alexander Spott at [email protected].

About the Author

John Wallace | Senior Technical Editor (1998-2022)

John Wallace was with Laser Focus World for nearly 25 years, retiring in late June 2022. He obtained a bachelor's degree in mechanical engineering and physics at Rutgers University and a master's in optical engineering at the University of Rochester. Before becoming an editor, John worked as an engineer at RCA, Exxon, Eastman Kodak, and GCA Corporation.

Sponsored Recommendations

March 31, 2025
Enhance your remote sensing capabilities with Chroma's precision-engineered optical filters, designed for applications such as environmental monitoring, geospatial mapping, and...
March 31, 2025
Designed for compatibility with a wide range of systems, Chroma's UV filters are engineered to feature high transmission, superior out-of-band blocking, steep edge transitions...
March 31, 2025
Discover strategies to balance component performance and system design, reducing development time and costs while maximizing efficiency.
March 31, 2025
Explore the essential role of optical filters in enhancing Raman spectroscopy measurements including the various filter types and their applications in improving signal-to-noise...

Voice your opinion!

To join the conversation, and become an exclusive member of Laser Focus World, create an account today!