Mode selection and dispersion engineering in Bragg-like slot photonic crystal waveguides for hybrid light-matter interactions

• Published in: 光子学研究：英文版 2018, Vol.9 (1), p.54-60
• Main Authors: SAMUEL SERNA, WEIWEI ZHANG, THI HONG CAM HOANG, CARLOS ALONSO-RAMOS, DELPHINE MARRIS-MORINI, LAURENT VIVIEN, AND ERiC CASSAN
• Format: Article
• Language: English
• Subjects: 光子晶体; 波导; 通讯技术; 发展现状
• ISSN: 2327-9125; 2327-9125

We introduce a family of slot photonic crystal waveguides （SPhCWs） for the hybrid integration of low-index active materials in silicon photonics with energy-confinement factors of -30% in low-index regions. The pro- posed approach, which is based on a periodic indentation of the etched slot in the middle of the SPhCW, makes it possible to reconcile a simultaneously narrow and wide slot for exploiting the two modes of even symmetry of a SPhCW. The resulting mode-selection mechanism allows a flexible choice of the modes to be used. Furthermore, the proposed structure offers tremendous flexibility for adjusting the dispersive properties of the slot-confined modes, in particular of their slow-light effects. Flat band slow light in a bandwidth of about 60 nm with a group velocity dispersion factor IP2I below I ps2/mm is numerically demonstrated by this approach, corresponding to a normalized delay bandwidth product of around 0.4. These results, obtained from hollow-core periodic wave- guides that are directly designed in view of hybrid integration of active materials in mechanically robust structures （not based on free-standing membranes） could pave the way for the realization of on-chip Slow-light bio-sensing, active hybrid-silicon optoelectronic devices, or all-optical hybrid-silicon nonlinear functionalities.