[16a-B4-1~13] 3.11 Photonic structures and phenomena

[16a-B4-7] Large-scale photonic crystal ring meta-cavity realized by coupled L2 nanocavities

〇Eiichi Kuramochi^1,2, Akihiko Shinya^1,2, Kengo Nozaki^1,2, Kenta Takata^1,2, Masaya Notomi^1,2 (1.NTT-NPC, 2.NTT-BRL)

Keywords:photonic crystal, optical cavity, silicon photonics

We previously reported curved waveguides realized by coupled L2 nanocavities L2-CROWs) in 2D triangular lattice photonic crystal slab (Kuramochi et al., JSAP 2016 Spring 22a-S621-4.) Here we describe closed ring waveguide formed by curved L2-CROW, including 18-30 L2 nanocavities. Unlike the previous studies the number of the cavities are much larger and the layout of the cavities are not according to the specific symmetrical orientations of L2. Thanks to the small footprint and the high loaded Q factor (~0.6 million) of L2, we found meta-cavity modes in the ring L2-CROWs. Q of meta-cavity modes (several to ten thousands) were fairly high. By comparison of side-coupled and resonant-tunneling filter designs and the far-field patterns, it was suggested that the observed meta-cavity modes were similar with the ring-cavity modes formed in conventional Si ring waveguides. We discuss the impact of using the curved L2-CROW instead of the conventional ring waveguide.