Silicon Photonic Single-Segment IQ Modulator for Net 1 Tbps/λ Transmission Using All-Electronic Equalization

There is a continuous need to scale optical communication networks' capacity to cope with the exponential growth of data traffic. Silicon photonics (SiP) retains significant potential as a platform for optical transceivers due to its CMOS compatibility, despite its limited electro-optic bandwidth and high driving voltage requirements. Here we present the design and characterization of two single-segment C-band SiP in-phase quadrature modulators (IQM) that differ in the phase shifter length, and we analyze the design tradeoffs based on their transmission performance. The large-signal transmission experiments indicate that the long IQM supports higher data transmission rates, which has 36 GHz 6-dB bandwidth and 10.5 V DC V_π under 1 V reverse bias. With all-electronic equalization and on a single polarization, we transmit net 413 Gbps (95 Gbaud 32QAM) over 80 km of standard single-mode fiber (SSMF) under the 14.8% overhead concatenated forward error correction (C-FEC) BER threshold of 1.25 × 10 ⁻² . Using dual-polarization (DP) emulation and lookup table-based non-linear pre-distortion (NLPD), we demonstrate the transmission of 95 Gbaud DP-32QAM and 115 Gbaud DP-16QAM over 80 km of SSMF below the C-FEC BER threshold, corresponding to net rates of 827 Gbps and 800 Gbps, respectively. Moreover, we transmit 105 Gbaud DP-64QAM over 80 km below the 25% overhead soft-decision (SD) FEC BER threshold of 5 × 10 ⁻² ; featuring the first demonstration of net 1 Tbps transmission using an all-silicon IQM. Employing only electronic equalization and single-segment IQM preserves the conventional architecture of coherent networks and transceivers, and highlights the potential of SiP as a platform for next-generation 800G applications.