Dual-polarization ultra-wideband nanophotonic beamsplitter

ECIO 2019,Ghent University, Ghent, Belgium, 24 April 2019High-performance optical beam splitters are of fundamental importance for the development of advanced silicon photonics integrated circuits. However, the performance of state-of-the-art silicon nanophotonic splitters is limited in terms of bandwidth and polarization dependence. Here, we present a new beam splitter approach that exploits modal engineering in slotted waveguides to overcome these limitations, enabling ultra-broadband polarization-insensitive optical power splitting. The proposed splitter relies on a single-mode slot waveguide that is gradually transformed into two strip waveguides by a symmetric taper, yielding equal power splitting. Based on this concept, we experimentally demonstrate insertion loss and power imbalance lower than 1 dB for both, transverse-electric (TE) and transverse-magnetic (TM) polarizations in an unprecedented bandwidth of 390 nm (1260 - 1650 nm).This work has been funded in part by the Spanish Ministry of Science, Innovation and Universities under grants TEC2015-71127-C2-1-R (FPI scholarship BES-2016-077798) and IJCI-2016-30484; and the Community of Madrid (P2018/NMT-4326). This project has received funding from the Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant No. 734331. This work has been partially funded by the Agence National pour la Recherche, Project MIRSPEC (ANR-17-CE09-0041) and the H2020 European Research Council (ERC) (ERC POPSTAR 647342)