Rigorous reflectance performance analysis of Si3N4 self-suspended subwavelength gratings

In this paper, we make an investigation into the reflectance performance of the Si3N4 self-suspended subwavelength grating (SSG) via changing several parameters including the incident wavelength, the grating period, the grating thickness and the grating filling ratio. For TM polarization of incidence, numerical results by the rigorous coupled-wave method reveal that the reflectance spectrum of the Si3N4 SSG has a narrow linewidth (less than 1 nm), high peak reflectance (100%), and low side bands (less than 0.5%) simultaneously in the optical telecommunication wavelength region. By using a micro-electromechanical-systems actuator, it is believed that the Si3N4 SSG should serve as tunable optical filters in optical telecommunication systems.