[12a-N321-1~10] 3.11 Photonic structures and phenomena

▲ [12a-N321-1] Analysis on light propagation properties of helical edge states supported in square-lattice photonic topological insulators

〇(M1)Chengkun Zhang^1,2, Hironobu Yoshimi^1,2, Yasutomo Ota³, Satoshi Iwamoto^1,2 (1.RCAST, 2.IIS, 3.Keio Univ.)

Keywords:photonic topological insulator, photonic waveguide, photonic crystals

Semiconductor topological photonic crystals (PhCs) enabling robust light transport gather attention because of their potential applications to integrated photonics. One of the widely studied topological PhCs is a hexagonal-lattice photonic topological insulators (PTIs) supporting counter-propagating helical edge states. However, the edge states discovered are above the light line, limiting the propagation length due to non-negligible radiation loss. Previously, we have reported a design of square-lattice PTIs supporting helical edge states below the light line. In this study, we numerically investigate the light propagation properties of the edge states and demonstrate robust light propagation immune to sharp bends in waveguides.