Complexity-Reduced Equalization for 200 Gbit/s PON Downstream Systems Based on SSB Modulation and Direct Detection

doi:10.12142/ZTECOM.202601008

ZTE Communications ›› 2026, Vol. 24 ›› Issue (1): 56-64.DOI: 10.12142/ZTECOM.202601008

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Complexity-Reduced Equalization for 200 Gbit/s PON Downstream Systems Based on SSB Modulation and Direct Detection

Yang Tao¹(), Huang Xingang², Ma Zhuang², Zhong Yiming², Huang Xiatao², Liu Bo²

^1.State Key Lab of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876，China
^2.ZTE Corporation, Shanghai 201203, China

Received:2024-06-26 Online:2026-03-25 Published:2026-03-17
About author:Yang Tao (yangtao@bupt.edu.cn) is an associate professor at the School of Electronic Engineering, Beijing University of Posts and Telecommunications (BUPT), China. He received his PhD degree in information and communication engineering from BUPT in 2019, followed by a postdoctoral fellowship in Electronic Science and Technology. His research interests include ultra-high-speed optical transmission, digital signal processing algorithms for optical communications, and intelligent optical network monitoring and management. He has authored or co-authored over 70 papers in prestigious journals and conferences like Optics Express and OFC, and holds more than 12 patents. He also serves as a guest editor and reviewer for several international journals.
Huang Xingang is a senior expert in technical pre-research with the Fixed Network Product Line, ZTE Corporation. He has long been engaged in the research and standardization of optical access technologies.
Ma Zhuang is the Head of Fixed Network Product Technology Pre-Research Department at ZTE Corporation. His work focuses on the pre-research, planning, and development of fixed broadband and optical access products. He has published more than 10 technical papers and is the inventor of over 20 granted patents.
Zhong Yiming is a senior engineer with the Fixed Network Pre-research Department, ZTE Corporation. His research centers on the R&D and innovation of PON products, with a primary focus on 50G PON system architecture design and algorithm research. He actively participates in PON standardization in ITU-T SG15, CCSA, and other industrial standards organizations, and has submitted numerous international standard contributions. He holds rich technical expertise in PON systems and has been granted multiple national invention patents.
Huang Xiatao is currently a technology research engineer at ZTE Corporation. He received his PhD degree in information and communication engineering from University of Electronic Science and Technology of China in 2023. His research interests include ultra-high-speed optical transmission, digital signal processing algorithms for optical coherent communications, and optical intelligent access system. He has held more than 6 patents.
Liu Bo is a chief pre-research engineer of OAN Product Line, ZTE Corporation. His research focuses on the pre-research of PON technologies.
Supported by:
ZTE Industry?University?Institute Cooperation Funds(HC?CN?20230105001);National Natural Science Foundation of China(62001045)

Abstract

Abstract:

The 200 Gbit/s passive optical network (PON) is most likely to be the next-generation scheme following 50G PON. The cost-effective direct detection (DD) system is the economical choice. However, larger-capacity DD systems will face much more serious power fading caused by chromatic dispersion (CD) combined with square-law DD and thereby significantly increases the complexity of equalization algorithms. In this paper, a 200 Gbit/s Nyquist 4-level pulse amplitude modulation (PAM4) single side-band (SSB) modulation-DD downlink scheme is designed, and a low complexity quadratic-nonlinear equalizer is proposed for this system. The computational complexity of the quadratic nonlinear equalizer is about 28% of that of the conventional Volterra nonlinear equalizer, while still exhibiting excellent nonlinear equalization ability. Simulation results for the 200 Gbit/s system with 20 km fiber transmission show that it can achieve a power budget of 29 dB, while a 30.4 dB power budget is obtained in the 50 Gbit/s experimental transmission.

Key words: 200 Gbit/s passive optical network, single side band modulation, direct detection, equalization

Yang Tao, Huang Xingang, Ma Zhuang, Zhong Yiming, Huang Xiatao, Liu Bo. Complexity-Reduced Equalization for 200 Gbit/s PON Downstream Systems Based on SSB Modulation and Direct Detection[J]. ZTE Communications, 2026, 24(1): 56-64.

Figures/Tables 10

Figure 1 200 Gbit/s Nyquist PAM4 SSB-DD PON downlink system scheme

Figure 2 Simulation setup of 200 Gbit/s Nyquist PAM4 SSB transmission over 20 km SSMF

Table 1 Main parameters of simulation system

Parameter	Value	Parameter	Value
Bit rate	200 Gbit/s	DAC/ADC sampling rate	200 GSa/s
DAC/ADC ENOB	8	Laser linewidth	10 MHz
MZM extinction ratio	20 dB	SOA noise figure	7.5 dB
Dispersion coefficient	16.5 ps/nm/km	PIN responsiveness	0.8 A/W
PIN thermal noise	1.2e-11 A/Hz^(1/2)	Receiver bandwidth	55 GHz

Figure 3 BER versus CSPR under a 20 km transmission simulation

Figure 4 Launched power versus BER

Figure 5 BER versus filter length at -9 dBm received optical power

Figure 6 BER vs ROP under a 20 km transmission simulation

Figure 7 20 km 25 GBaud PAM4 single sideband modulation-direct detection point-to-point downlink experimental platform

Figure 8 BER vs CSPR for 20 km transmission experiment

Figure 9 BER vs ROP under a 20 km transmission experiment

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Complexity-Reduced Equalization for 200 Gbit/s PON Downstream Systems Based on SSB Modulation and Direct Detection

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