Demonstration of 4 × 100 Gbit/s PAM-4 Transmission Over 40 km in an IM/DD System Based on Narrow Band DMLs

Kaihui Wang,Jianjun Yu,Miao Kong,Mingming Zhao

doi:10.1109/jphot.2020.2993670

Abstract

We demonstrate a four-lane wavelength division multiplexing (WDM) intensity modulation and direct detection (IM/DD) system at O-band. The 3-dB bandwidth of directly modulated lasers (DMLs) in this experiment is only 15 GHz. To support 100-Gbit/s/lane PAM-4 transmission in each lane, digital pre-equalization and advanced receiver-side DSPs are adopted to compensate for bandwidth limitation. Moreover, semiconductor optical amplifier (SOA) is utilized at the receiver to compensate for the optical power loss during fiber transmission so that 40-km transmission distance can be achieved. To the best of our knowledge, it is the first time to successfully transmit 400-Gbit/s PAM-4 signals over 40-km SSMF with 15-GHz DMLs.

Highlights

Driven by the upcoming high-speed services, such as clouding networking, 5G/6G, and VR/AR applications, the metro traffic has been explosively increased and surpassed the long-haul traffic in recent years [1,2,3]
We demonstrate a four-lane wavelength division multiplexing (WDM) intensity modulation and direct detection (IM/DD) system at O-band
In the transmitter-side DSPs, the pseudo-random binary sequence (PRBS) data is firstly mapped into pulse amplitude modulation (PAM)-4 symbols

Summary

Introduction

Driven by the upcoming high-speed services, such as clouding networking, 5G/6G, and VR/AR applications, the metro traffic has been explosively increased and surpassed the long-haul traffic in recent years [1,2,3]. Considering large-scale deployment scenarios, the IM/DD system is the most attractive solution to cost effectively achieve a data rate of 100 Gbit/s/channel and a transmission distance of 20 km or beyond. The non-return-to-zero (NRZ) coding is still widely spread in short reach systems, the spectral efficiency (SE) of NRZ is only 1bit/s/Hz. To support higher capacity, the advanced modulation formats with higher SE should be adopted. Compared with discrete multi-tone (DMT) and carrier-less amplitude phase (CAP) modulation, pulse amplitude modulation (PAM) has lower complexity and power consumption in hardware implementation [3]. PAM is an ideal modulation format for IM/DD systems. To further improve the transmission rate and meet the demand of 400G data connection, four-lane IM/DD transmission system with low transceiver cost and simple system integration is a promising solution [2]

Methods

Results

Conclusion