Four-Dimensional Silicon Photonic Dual-Polarization Direct Detection Receiver

The advancement of next-generation fiber-optic transmission requires higher-speed transceivers where cost, footprint and power consumption are of critical consideration. Photonic integration provides an effective solution to reduce the cost and footprint of the transceivers by integrating diverse optoelectronic devices on chips. In particular, complementary metal–oxide–semiconductor (CMOS)-compatible silicon photonics (SiP) has been considered as a promising platform with high integration density and high yield. Since a coherent receiver relies on a local laser based on heterogeneous III-V materials, it is highly desired to eliminate the laser by developing integrated SiP DD receivers. In this paper, by leveraging the polarization diversity technique, we demonstrate the first four-dimensional (I, Q, X, Y) integrated dual-polarization (DP) direct detection (DD) receiver with an automated silicon polarization controller followed by two SiP single-polarization carrier-assisted differential detection (CADD) receivers. A 528-Gb/s polarization-division multiplexing 16-QAM OFDM signal was transmitted over an 80-km single-mode fiber (SMF) link and detected using the integrated SiP DP-CADD receiver, with a bit error ratio below the 24% soft-decision forward error correction threshold. To the best of our knowledge, we achieved a record 426-Gb/s net capacity and 11.83-b/s/Hz net ESE for an integrated DD receiver.