4 × 32-Gbps Block-Wise QPSK 1200-km SSMF Direct Detection Transmission Based on Delta-Sigma Virtual Carrier Generation

Zhuo Chen,Qi Yang,Jiaqi Huang,Ziqiang Wu,Junxiang Ke,Zhongzhong Wang,Xueyuan Ao,Lilin Yi,Shenmao Zhang

doi:10.1109/jphot.2019.2953358

Abstract

Direct detection (DD) is one of the most attractive solutions for short and medium reach optical fiber transmission in comprehensive consideration of digital signal processing (DSP), power consumption, and cost. Various single side band (SSB) DD techniques have been widely investigated to detect and process the complex signal. In this paper, we propose a novel approach which uses only high-speed digital input/outputs (IO) to generate both quadrature phase shift keying (QPSK) signal and virtual carrier signal. A transmission of 4 × 32 Gb/s QPSK signal over 1200-km standard single mode fiber (SSMF) in block-wise manner has been successfully demonstrated. Only a single polarization in-phase-and-quadrature (IQ) modulator and one single photodiode (PD) are used for each channel. Compared with conventional DSP of coherent detection, the DSP in the proposed scheme is also simplified that only fixed frequency compensation is required without additional phase noise elimination. The overall system complexity has been greatly reduced.

Highlights

Fast growing demand on metro and data center traffic involves great challenges in realizing cost-effective and high-performance direct detection systems at data rates beyond 100 Gb/s and transmission reaches over 100 km [1]–[5]
We propose a novel approach which uses only high-speed digital input/outputs (IO) to generate both quadrature phase shift keying (QPSK) signal and virtual carrier signal
Technique has been reported that a 40-Gb/s orthogonal frequency division multiplexing (OFDM) signal is transmitted over 80-km standard single mode fiber (SSMF) within a single polarization [1]

Summary

Introduction

Fast growing demand on metro and data center traffic involves great challenges in realizing cost-effective and high-performance direct detection systems at data rates beyond 100 Gb/s and transmission reaches over 100 km [1]–[5]. For the needs of systems with higher rate and longer reaches, various SSB DD techniques have been widely investigated to detect the complex signal using a single or a few photodiodes, such as block-wise phase switching [1], Stokes vector detection (SVD) [2], and Kramers-Kronig (K-K) detection [3]–[5]. Technique has been reported that a 40-Gb/s orthogonal frequency division multiplexing (OFDM) signal is transmitted over 80-km SSMF within a single polarization [1]. A 5-channel wavelength-division multiplexing (WDM) DD transmission over 80 km SSMF has been demonstrated with a net data rate per channel of 432 Gb/s [3] For such technique, allocating an assisted optical carrier is critical for K-K detection. Compared with the existing various SSB-DD techniques, the system complexity is greatly simplified

Principle

Experimental Setup

Results

Conclusion