Preferential-order waveguide grating couplers: a comparative rigorous analysis using the finite-difference time-domain method.
We rigorously analyze and compare preferential-order waveguide grating output couplers using the finite-difference time-domain method in the total-field/scattered-field formulation for TE and TM polarizations. Four kinds of preferential-order grating couplers are studied: volume holographic grating couplers, slanted parallelogrammic surface-relief grating couplers, double-corrugated surface-relief grating couplers, and reflecting-stack surface-relief grating couplers. The outcoupling efficiencies and branching ratios of the couplers, revealing their preferentiality, are calculated and compared with the rigorous coupled-wave analysis leaky-mode method. In addition, their performance is examined in terms of the main design parameters and the excitation wavelength.
School of Electrical and Computer Engineering National Technical University of Athens, Athens, Greece 15773. arpapad@mail.ntua.gr
Aristeides D
AD
Papadopoulos
Elias N
EN
Glytsis