Silicon Photonic Segmented Modulator-Based Electro-Optic DAC for 100 Gb/s PAM-4 Generation

We report on the design and characterization of a silicon-on-insulator traveling-wave multi-electrode Mach-Zehnder modulator (MZM). The 2-bit electro-optic (EO) digital-to-analog converter is formed by dividing a series push-pull MZM into two segments, one for each bit. The EO bandwidth of the longer segment of the MZM is measured to be 48 GHz at 0 V reverse bias. We operate the device at speeds up to 50 GBd to create a four-level pulse amplitude modulation signal, and thus generating 100 Gb/s on a single wavelength without signal processing at the transmitter or the receiver. The pre-forward error correction (FEC) bit error rate is estimated to be lower than the hard-decision FEC threshold of 3.8 × 10^-3 over 1 km of standard single-mode fiber, and thus leading to error-free transmission at 100 Gb/s.