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.
Papadopoulos
Aristeides D
AD
School of Electrical and Computer Engineering National Technical University of Athens, Athens, Greece 15773. arpapad@mail.ntua.gr
Glytsis
Elias N
EN