112 GBaud PAM4 Barium Titanate Coupling Modulated Ring Modulator Monolithically Integrated on a Silicon Substrate

We demonstrate a BTO coupling modulated ring modulator featuring a $500 \mu \mathrm{m}$ phase shifter, $4.8 \mathrm{~V} V_{\pi}$ with < 1 dB insertion loss enabling ultra-dense and low power consumption optical interfaces delivering 112 GBaud PAM4.