Electromagnetic Field Investigation of Double Groove for Reflective Zeroth-order Suppression

With zeroth-order suppression, a double-groove reflective grating for dual-port reflection beam splitter is studied in this paper. Under normal incidence, the grating obtains great efficiencies for both TE and TM polarizations. The parameters of the double-groove grating are derived using rigorous coupled-wave analysis. The finite element method and the simulated annealing algorithm are also presented to make sure that the ideal parameters are obtained. Total efficiencies of 98.95% for TE polarization and 99.30% for TM polarization are realized at an incidence wavelength of 1550 nm. In the meantime, the efficiencies of TE polarization and TM polarization at ± 1st orders are 48.15% and 46.26%, while at zeroth order, they are being effectively suppressed at 2.41% and 6.56%. The suggested grating has exceptional qualities and performs admirably.