A new structure of microstructure reflection three-port beam splitter grating is described in this paper. The grating includes two dielectric layers and a metal slab on the substrate, where incident waves are reflected into the zeroth-order and the ± first-order with polarization-independent property. With the optimized grating profile, reflection efficiencies’ ratios between the first-order and the zeroth-order can reach 0.998 and 1.001 for TE and TM polarizations, respectively. Especially, the reflection grating can diffract efficiencies more than 30% into the ± first-order and the zeroth-order with the incident angular bandwidth of −1.9–1.9[Formula: see text] for TM polarization, which can have merits compared with single-layer transmission grating.
Polarization-Independent Multiwavelength-Switchable Filter Based on Polarization Beam Splitter and Fiber Coupler