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Methods and apparatus for vertical coupling from dielectric waveguides

United States Patent

June 17, 2014
View the Complete Patent at the US Patent & Trademark Office
Sandia National Laboratories - Visit the Intellectual Property Management and Licensing Website
A frequency-chirped nano-antenna provides efficient sub-wavelength vertical emission from a dielectric waveguide. In one example, this nano-antenna includes a set of plasmonic dipoles on the opposite side of a SiYV.sub.4 waveguide from a ground plane. The resulting structure, which is less than half a wavelength long, emits a broadband beam (e.g., >300 nm) that can be coupled into an optical fiber. In some embodiments, a diffractive optical element with unevenly shaped regions of high- and low-index dielectric material collimates the broadband beam for higher coupling efficiency. In some cases, a negative lens element between the nano-antenna and the diffractive optical element accelerates the emitted beam's divergence (and improves coupling efficiency), allowing for more compact packaging. Like the diffractive optical element, the negative lens element includes unevenly shaped regions of high- and low-index dielectric material that can be designed to compensate for aberrations in the beam emitted by the nano-antenna.
Yaacobi; Ami (Cambridge, MA), Cordova; Brad Gilbert (Cambridge, MA), Sun; Jie (Cambridge, MA), Watts; Michael (Hingham, MA)
Massachusetts Institute of Technology (Cambridge, MA)
13/ 798,499
March 13, 2013
GOVERNMENT SUPPORT This invention was made with government support under Grant No. DE-AC04-94AL85000 awarded by the Department of Energy. The government has certain rights in this invention.