Single-lane 200G+ high speed optical transmission using single-DAC for data center interconnects

Abstract

Propelled by bandwidth-hungry cloud services, the ongoing growth of intra-datacenter traffic drives the development of high-speed short-reach transceivers, which calls for next generation optical interfaces of 800-GE or even 1.6-TbE. Conventional intensity-modulation direct-detection (IM/DD) systems still dominate the market for high speed short reach optical interconnects due to its simplicity and low cost compared with coherent solutions. Several advanced techniques to achieving net data rates around 200∼250 Gbps have been demonstrated. Effective digital signal processing (DSP) for signal recovery are always used in these systems, including digital pre-distortion, digital timing recovery, feed-forward and decision feedback equalization (FFE/DFE) and stronger forward error correction. Probabilistic shaping (PS) has been introduced for 200G+ per lane IM/DD systems. Semiconductor optical amplifier (SOA) and PS can be potentially used for 200G+ per lane IM/DD systems at O-band over 10 km SMF. There are two main transmission impairments: the nonlinear impairments from the nonlinear region of the electro-optical components, and linear impairments from the bandwidth constraint of the optoelectronic devices and chromatic dispersion. Single-lane 200G+ transmission is difficult to realize due to the nonlinear impairments and the strong bandwidth constraint of optoelectronic devices. In recent years, we have experimentally demonstrated several 200G+ per lane IM/DD short-reach transmission system, making it a promising scheme for data center short-reach applications.