120 GSa/s BiCMOS AMUX for 360 Gbit/s High-Information-Rate Signal Generation Demonstrated in 10 km IM/DD System

Abstract

Future high-speed optical communication requires continuous increases in both information rate (IR) and symbol rate. An analog multiplexer (AMUX) interleaves individually generated tributaries at lower rates to form an interleaved high-speed signal, which allows to reuse cost- and power-efficient low bandwidth CMOS DACs to obtain a broadband signal. A 120 GSa/s BiCMOS AMUX is designed based on a high-linearity topology, which enables to generate signal carrying a high information rate (IR). A calibration procedure is adopted to maximize the effective vertical resolution of the output signal. Using this BiCMOS AMUX, real-valued digital-subcarrier-multiplexed probabilistically-constellation-shaped QAM signal is generated for 10 km fiber transmission based on intensity modulation and direct detection (IM/DD). A per-electrical-lane-normalized net data rate (NNDR) of 360 Gbit/s/lane is achieved after 10 km fiber transmission, resulting in a per-electrical-lane-normalized net IR (NNIR) of 3 bit/sym/lane, which is the highest NNIR reported with AMUX-based signal generation. The record NNIR shows the potential of the BiCMOS AMUX to support future high-speed optical transmission in terms of IR and symbol rate.