Bragg filter bandwidth engineering in subwavelength grating metamaterial waveguides.

Bragg gratings are fundamental building blocks for integrated photonic circuits. In the high-index contrast silicon-on-insulator material platform, it is challenging to accurately control the grating strength and achieve narrow spectral bandwidths. Here we demonstrate a novel Bragg grating geometry utilizing a silicon subwavelength grating (SWG) waveguide with evanescently coupled periodic Bragg loading segments placed outside the SWG core. We …