PhD defence of Hao Sun - Waveguide Bragg gratings using subwavelength grating waveguide in silicon photonics platform

Abstract

Silicon photonics (SiP) is an emerging technique that can enable compact photonic integrated devices with the high performance. Over the decades, numerous active and passive devices have been well developed, e.g., modulators, optical micro-ring resonators, waveguide Bragg gratings (WBGs), and photodetectors. Recently, subwavelength grating (SWG) has attracted lots of attentions due to its lower propagation loss, the flexibility in tailoring effective indices, and the unique feature in manipulating the polarization. Various SWG waveguide-based SiP devices have been demonstrated, such as the SWG WBGs, SWG micro-ring resonators, SWG based crossings, and SWG assisted contra-directional couplers, etc. Thanks to the characteristics of the SWG structure, the performance of these photonic integrated devices has been largely improved. In this thesis, we aim to improve the performance of WBGs by using SWG structures. Several SWG WBG structures are developed and experimentally demonstrated in three categories: 1) the management of the group delay; 2) the management of resonances; 3) the management of the polarization.