title: Polarization-independent nonuniform grating couplers on silicon-on-insulator.
abstract: Grating couplers are proposed for polarization-independent coupling of light between a single-mode fiber and a 220-nm-thick channel waveguide on silicon-on-insulator. The grating couplers have nonuniform grating periods that are composed of the intersection or union of a set of two near-optimal TE- and TM-grating periods. The proposed grating couplers have a coupling efficiency greater than 20% and polarization dependent loss (PDL) lower than 0.5 dB within 3-dB bandwidth in design. For the evaluation of the design concept, a fabricated intersection grating coupler has the PDL of less than 0.8 dB within the wavelength range of 1540 to 1560 nm, and the coupling efficiency is ∼18%.
authors.forename: Jeong Hwan
authors.initials: JH
authors.lastname: Song
authors.forename: Fuad E
authors.initials: FE
authors.lastname: Doany
authors.forename: Ashenafi K
authors.initials: AK
authors.lastname: Medhin
authors.forename: Nicolas
authors.initials: N
authors.lastname: Dupuis
authors.forename: Benjamin G
authors.initials: BG
authors.lastname: Lee
authors.forename: Frank R
authors.initials: FR
authors.lastname: Libsch