title: Preferential input-waveguide grating couplers: rigorous analysis using the pseudospectral time-domain method.
abstract: Preferential input-waveguide grating couplers are rigorously analyzed using the pseudospectral time-domain method in the total field/scattered field formulation for TE and TM polarizations in conjunction with the convolutional perfect matching layer approach. Four kinds of preferential input-waveguide grating couplers are studied: the volume holographic grating coupler, the slanted parallelogrammic surface-relief grating coupler, the double-corrugated surface-relief grating coupler, and the reflecting-stack surface-relief grating coupler. Coupler's input coupling efficiencies to various waveguide modes are calculated. In addition, a comparative study of performance is presented in terms of the main design parameters and the operational free-space wavelength.
authors.affiliation: School of Electrical and Computer Engineering, National Technical University of Athens, Athens 15773, Greece. arpapad@mail.ntua.gr
authors.forename: Aristeides D
authors.initials: AD
authors.lastname: Papadopoulos
authors.forename: Elias N
authors.initials: EN
authors.lastname: Glytsis