Implementation of a graded-index medium by use of subwavelength structures with graded fill factor

Uriel Levy*, Maziar Nezhad, Hyo Chang Kim, Chia Ho Tsai, Lin Pang, Yeshaiahu Fainman

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

63 Scopus citations


We present a novel configuration for the implementation of subwavelength-based graded-index devices. The proposed concept is based on the etching of one-dimensional subwavelength gratings into a high-index slab waveguide to achieve the desired effective index distribution. A graded-index profile can be achieved by gradually modifying the duty ratio of the grating along the horizontal axis, while the beam is confined in the vertical direction by the slab waveguide. On the basis of this concept, novel graded-index lenses and waveguides are both proposed and characterized numerically by use of finite-difference time-domain and finite-element analysis. The proposed devices can be used for guiding, imaging, optical signal processing, mode matching, coupling, and other applications while offering the intrinsic advantages of on-chip integration such as miniaturization, eliminating the need to align each component separately, and compatibility with standard microfabrication techniques for manufacturability.

Original languageAmerican English
Pages (from-to)724-733
Number of pages10
JournalJournal of the Optical Society of America A: Optics and Image Science, and Vision
Issue number4
StatePublished - Apr 2005
Externally publishedYes


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