[15p-B508-8~13] 3.15 Silicon photonics and integrated photonics

▲ [15p-B508-12] High-speed optical modulation by III-V/Si hybrid MOS optical modulator with low parasitic capacitance

〇(P)Qiang Li¹, Chong Pei Ho¹, Junichi Fujikata², Masataka Noguchi², Shigeki Takahashi², Kasidit Toprasertpong¹, Shinichi Takagi¹, Mitsuru Takenaka¹ (1.Univ. Tokyo, 2.PETRA)

Keywords:Optical modulator, Si photonics, III-V/Si hybrid integration

In this study, we demonstrated a high-speed optical modulation at 12.5 Gbit/s by III-V/Si hybrid MOS optical modulator. To achieve a high-speed optical modulation, a low resistance-capacitance constant is critical. The width of Si rib waveguide was optimized to better balance the optical modulation bandwidth and modulation efficiency. A Si rib waveguide embedded in SiO₂ layer was adopted to eliminate parasitic capacitances. Moreover, a heavily doped InGaAs/InP layer was inserted below n-type contact to realize a low contact resistivity. In addition, both the doping densities in InGaAsP and Si layers were optimized to enable a low resistance. As a result, the trade-off relationship between data rate and modulation efficiency was successfully improved.