Presentation Information
[C-3_C-4-32]Design of Submillimeter-Scale a-Si-Loaded Slow-Light TFLN Optical Modulator
〇Keisuke Kawahara1, Kazuya Miura1, Tsuyoshi Horikawa1, Moataz Eissa1, Yoshitaka Oiso1, Ryuga Yajima2, Yoshiki Katagiri2, Nobuhiko Nishiyama1,3 (1. Institute of Science Tokyo, 2. NGK Insulators, LTD, 3. Next-generation Semiconductor Eco-system Co-creation Center)
Keywords:
Optical modulator,Thin-film lithium niobate,Slow light,Photonic integrated circuit,Electronics-photonics convergence
Thin-film lithium niobate (TFLN) Mach–Zehnder optical modulators have attracted considerable attention for multi-Tb/s-class optical interconnects. However, reducing the driving voltage requires phase shifters with lengths on the order of several centimeters, which increases the device footprint and RF loss. In silicon optical modulators, high-efficiency devices with phase shifters only a few hundred micrometers long have been reported by enhancing light–matter interaction using slow-light structures. Similar length reduction is expected to be effective for TFLN modulators as well, but forming fine structures in LN is not straightforward. We have previously proposed an amorphous-silicon-loaded TFLN waveguide that provides strong optical confinement without etching LN, and have demonstrated optical waveguiding, designed velocity-matched electrodes, and analyzed high-speed modulation characteristics. In this study, we design a slow-light optical modulator based on amorphous-silicon-loaded TFLN and report that it has the potential to achieve both high efficiency with VπL < 1 V and a broad bandwidth on the order of 200 GHz.