Bragg filter bandwidth engineering in subwavelength grating metamaterial waveguides. Opt Lett 2019 Feb 15;44(4):1043-1046
Date
02/16/2019Pubmed ID
30768051DOI
10.1364/OL.44.001043Scopus ID
2-s2.0-85061526862 (requires institutional sign-in at Scopus site) 46 CitationsAbstract
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 report experimental 3 dB filter bandwidths in a range from 8 nm to 150 pm by adjusting the distance of the Bragg loading segments from the core and the relative phase shift of the segments on the two sides of the waveguide, with a structure that has a minimum feature size of 100 nm.