Formation of 1 × 3 splitting by embedded double-layer reflective grating under second Bragg illumination

Abstract

In order to obtain a [Formula: see text] grating with high performance, we designed a double-layer reflective grating beam splitter with a covering layer at a wavelength of 1550 nm. We obtain a better grating structure by modal analysis and rigorous coupled-wave method. The reflectivity of the three diffraction orders for the grating is close to 33.3%. The optimized data show that the grating beam splitter has a large period process tolerance for TE polarization. The grating performance has high incident performance and uniform splitting effect.