A five-layer grating structure is designed to generate polarization-independent filter in the telecom band. It is demonstrated theoretically that in the five-layer grating structure, by adjusting the thickness of the interlayer sandwiched between two dielectric layers with high permittivity, the resonance wavelengths of transverse magnetic (TM)- and transverse electric (TE)-polarized light can locate at the same wavelength with the same guide-mode resonance structure parameters and the filter ef
