title: Quasi-free-space optical coupling between diffraction grating couplers fabricated on independent substrates.
abstract: Optical coupling between preferential-order volume diffraction grating couplers fabricated on independent substrates is demonstrated. The coupling efficiency between gratings is quantified as a function of both grating and waveguide fabrication technology and relative angular position of the two substrates. A maximum grating-to-grating coupling efficiency of 31% is reported for coupling between two nonoptimized, nonfocusing, unpatterned volume grating couplers.
authors.affiliation: Microelectronics Research Center, Georgia Institute of Technology, Atlanta, Georgia 30332-0269, USA. gt2925a@prism.gatech.edu
authors.forename: Anthony V
authors.initials: AV
authors.lastname: Mulé
authors.forename: Ricardo
authors.initials: R
authors.lastname: Villalaz
authors.forename: Thomas K
authors.initials: TK
authors.lastname: Gaylord
authors.forename: James D
authors.initials: JD
authors.lastname: Meindl