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

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 aspott@uwashington.edu.

 


More Laser Focus World Current Issue Articles


More Laser Focus World Archives Issue Articles

Most Popular Articles


Click here to have your products listed in the Laser Focus World Buyers Guide.

Article Archive

View Laser Focus World past articles now.

Social Activity

  •  
  •  
  •  
  •  
  •  
Copyright © 2007-2014. PennWell Corporation, Tulsa, OK. All Rights Reserved.PRIVACY POLICY | TERMS AND CONDITIONS