下一代光接入网中物理层关键技术研究进展

doi:10.3969/j.issn.0255-8297.2020.04.007

摘要/Abstract

摘要： 5G和数据密集型应用的兴起对下一代光接入网的容量提出了新的挑战.作为最成熟的宽带光纤接入技术，无源光网络（passive optical network，PON）受到了广泛关注.为了在满足功率预算的前提下实现更高的传输速率，提升物理层性能的关键技术一直是该领域的研究热点，同时尽可能地降低系统成本对PON的大规模部署有着重大意义.该文梳理并总结了光接入网中物理层关键技术的研究进展.介绍了PON标准的演进和现状，分析了下一代PON面临的挑战和成因，重点阐述了数字均衡技术、高阶调制格式、光放大、前向纠错、非线性串扰实验分析以及低成本相干检测等关键技术及其研究进展，并综述了当前相关工作的研究成果.

关键词: 无源光网络, 均衡技术, 调制格式, 光放大, 前向纠错, 非线性串扰, 低成本相干检测

Abstract: The rapid growth of 5G and data-intensive applications poses new challenges to the capacity of next-generation optical access networks. As the most mature broadband fiber access technology, passive optical networks (PON) has drawn widespread attention. In order to achieve a higher transmission rate under the premise of meeting the power budget, the key technology to improve the performance of the physical layer has always been a research hotspot in this field. Meanwhile, it is of great significance to reduce the system cost as much as possible for the large-scale deployment of PON. In this paper, we describe and summarize the research progress of key physical layer technologies in optical access network. We introduce the evolution and current status of the PON standards, analyze the challenges and causes in the next-generation PON, and focus on the key technologies such as digital equalization technology, high-order modulation formats, optical amplification, forward error correction, experimental analysis of nonlinear crosstalk, and low-cost coherent detection and their research progress. We also review the current research achievements of relevant works.

Key words: passive optical networks, equalization technique, modulation format, optical amplification, forward error correction, nonlinear crosstalk, low-cost coherent detection

中图分类号:

TN929.18

骆思雨, 许岩, 李正璇, 宋英雄, 汪敏. 下一代光接入网中物理层关键技术研究进展[J]. 应用科学学报, 2020, 38(4): 612-629.

LUO Siyu, XU Yan, LI Zhengxuan, SONG Yingxiong, WANG Min. Progress in Key Technologies of Physical Layer in Next Generation Optical Access Networks[J]. Journal of Applied Sciences, 2020, 38(4): 612-629.

参考文献

[1] Kumari M, Sharma R, Sheetal A. Passive optical network evolution to next generation passive optical network:a review[C]//2018 6th Edition of International Conference on Wireless Networks & Embedded Systems, Rajpura, India, November, 2018:102-107.
[2] Van Veen D, Houtsma V. Strategies for economical next-generation 50G and 100G passive optical networks[J]. Journal of Optical Communications and Networking, 2020, 12(1):A95-A103.
[3] Wey J S. The outlook for PON standardization:a tutorial[J]. Journal of Lightwave Technology, 2020, 38(1):31-42.
[4] Harstead E, van Veen D, Houtsma V, et al. Technology roadmap for time-division multiplexed passive optical networks (TDM PONs)[J]. Journal of Lightwave Technology, 2018, 37(2):657-664.
[5] Huang M Y, Cai P F, Li S, et al. 56 GHz waveguide Ge/Si avalanche photodiode[C]//Optical Fiber Communications Conference and Exposition, San Diego, USA, March, 2018:1-3.
[6] Li Z X, Yi L L, Ji H L, et al. 100 Gb/s TWDM-PON based on 10G optical devices[J]. Optics Express, 2016, 24(12):12941-12948.
[7] Zhang K, Zhuge Q B, Xin H Y, et al. Design and analysis of high-speed optical access networks in the O-band with DSP-free ONUs and low-bandwidth optics[J]. Optics Express, 2018, 26(21):27873-27884.
[8] Houtsma V, van Veen D. Optical strategies for economical next generation 50 and 100G PON[C]//Optical Fiber Communications Conference and Exposition, San Diego, USA, March, 2019:1-3.
[9] Zhang J, Yu J J, Li X Y, et al. Demonstration of 100 Gb/s/λ PAM-4 transmission over 45 km SSMF using one 10G-class DML in the C-band[C]//Optical Fiber Communications Conference and Exposition, San Diego, USA, March, 2019:1-3.
[10] Li F, Zou D D, Sui Q, et al. Optical amplifier-free 100 Gbit/s/λ PAM-W transmission and reception in O-band over 40 km SMF with 10-G class DML[C]//Optical Fiber Communications Conference and Exposition, San Diego, USA, March, 2019:1-3.
[11] Miao X, Bi M H, He H, et al. Four-wave mixing effect reduction in O-band multi-wavelength NG-EPON system based on chirped DML[C]//Opto-Electronics and Communications Conference and Photonics Global Conference, Singapore, July, 2017:1-3.
[12] Bansal S. Optimal Golomb ruler sequence generation for FWM crosstalk elimination:soft computing versus conventional approaches[J]. Applied Soft Computing, 2014, 22:443-457.
[13] Zheng Q, Li W, Yan R, et al. XPM mitigation in WDM systems using split nonlinearity compensation[J]. IEEE Photonics Journal, 2019, 11(6):7205411.
[14] Lavery D, Erkilinc S, Bayvel P, et al. Recent progress and outlook for coherent PON[C]//Optical Fiber Communications Conference and Exposition, San Diego, USA, March, 2018:1-3.
[15] Li Z X, Xia J Q, Guo Y, et al. Investigation on the equalization techniques for 10G-class optics enabled 25G-EPON[J]. Optics Express, 2017, 25(14):16228-16234.
[16] Xia J Q, Xu T T, Li Z X, et al. Investigation on adaptive equalization techniques for 10Gglass optics based 100G-PON system[C]//Opto-Electronics and Communications Conference and Photonics Global Conference, Singapore, July, 2017:1-3.
[17] Xu T T, Xia J Q, Li Z X, et al. A simplified MLSE algorithm based on absolute distance measurement model[C]//Asia Communications and Photonics Conference, Guangzhou, China, November, 2017:1-3.
[18] Xu T T, Li Z X, Peng J J, et al. Decoding of 10-G optics-based 50-Gb/s PAM-4 signal using simplified MLSE[J]. IEEE Photonics Journal, 2018, 10(4):1-8.
[19] Wei J L, Giacoumidis E. 40 Gb/s/λ optical amplified PAM-4 PON with transmission over 30 km SMF using 10-G Optics and simple DSP[C]//Optical Fiber Communications Conference and Exhibition, Los Angeles, USA, March, 2017:1-3.
[20] Wei J L, Zhou J, Giacoumidis E, et al. DSP-based 40 Gb/s lane rate next-generation access networks[J]. Future Internet, 2018, 10(12):118.
[21] Diamantopoulos N P, Kobayashi W, Nishi H, et al. 56 Gb/s VSB-PAM-4 over 80 km using 1550-nm EA-DFB laser and reduced-complexity nonlinear equalization[C]//European Conference on Optical Communication, Gothenburg, Sweden, September, 2017:1-3.
[22] Chuang C Y, Chang W F, Wei C C, et al. Sparse Volterra nonlinear equalizer by employing pruning algorithm for high-speed PAM-4850 nm VCSEL optical interconnect[C]//Optical Fiber Communications Conference and Exposition, San Diego, USA, March, 2019:1-3.
[23] Gao F, Zhou S W, Li X, et al. 2×64 Gb/s PAM-4 transmission over 70 km SSMF using O-band 18G-class directly modulated lasers (DMLs)[J]. Optics Express, 2017, 25(7):7230-7237.
[24] Chen J, Tan A C, Li Z X, et al. 50 km C-band transmission of 50 Gb/s PAM4 using 10-G EML and complexity-reduced adaptive equalization[J]. IEEE Photonics Journal, 2018, 11(1):1-10.
[25] Reza A G, Rhee J K K. Nonlinear equalizer based on neural networks for PAM-4 signal transmission using DML[J]. IEEE Photonics Technology Letters, 2018, 30(15):1416-1419.
[26] Häger C, Pfister H D. Nonlinear interference mitigation via deep neural networks[C]//Optical Fiber Communications Conference and Exposition, San Diego, USA, March, 2018:1-3.
[27] Chuang C Y, Liu L C, Wei C C, et al. Convolutional neural network based nonlinear classifier for 112 Gbps high speed optical link[C]//Optical Fiber Communications Conference and Exposition, San Diego, USA, March, 2018:1-3.
[28] Yi L L, Li P X, Liao T, et al. 100 Gb/s/λ IM-DD PON using 20G-class optical devices by machine learning based equalization[C]//European Conference on Optical Communication, Rome, Italy, September, 2018:1-3.
[29] Yi L L, Liao T, Huang L Y, et al. Machine learning for 100 Gb/s/λ passive optical network[J]. Journal of Lightwave Technology, 2019, 37(6):1621-1630.
[30] Liao T, Xue L, Hu W S, et al. Unsupervised learning for neural network-based blind equalization[J]. IEEE Photonics Technology Letters, 2020, 32(10):569-572.
[31] Yi L L, Liao T, Xue L, et al. Neural network-based equalization in high-speed PONs[C]//Optical Fiber Communications Conference and Exhibition, San Diego, USA, 2020:1-3.
[32] Karanov B, Chagnon M, Thouin F, et al. End-to-end deep learning of optical fiber communications[J]. Journal of Lightwave Technology, 2018, 36(20):4843-4855.
[33] Miao X, Bi M H, Fu Y, et al. Experimental study of NRZ, duobinary, and PAM-4 in O-band DML-based 100G-EPON[J]. IEEE Photonics Technology Letters, 2017, 29(17):1490-1493.
[34] Zhang H B, Jiang N, Zheng Z, et al. Experimental demonstration of FTN-NRZ, PAM-4, and duobinary based on 10 Gbps optics in 100G-EPON[J]. IEEE Photonics Journal, 2018, 10(5):1-13.
[35] Xia J X, Li Z X, Li Y C, et al. Comparison of NRZ and duo-binary format in adaptive equalization assisted 10G-optics based 25G-EPON[J]. Optics Communications, 2018, 410:328- 332.
[36] Zhang J W, Wey J S, Yu J J, et al. Symmetrical 50 Gb/s/λ PAM-4 TDM-PON in O-band with DSP and semiconductor optical amplifier supporting PR-30 link loss budget[C]//Optical Fiber Communications Conference and Exposition, San Diego, USA, March, 2018:1-3.
[37] Zhang J, Yu J J, Wey J S, et al. SOA pre-amplified 100 Gb/s/λ PAM-4 TDM-PON downstream transmission using 10 Gbps O-band transmitters[J]. Journal of Lightwave Technology, 2020, 38(2):185-193.
[38] Bonk R. SOA for future PONs[C]//Optical Fiber Communications Conference and Exposition, San Diego, USA, March, 2018:1-3.
[39] Li C C, Chen J, Li Z X, et al. Demonstration of symmetrical 50 Gb/s TDM-PON in O-band supporting over 33 dB link budget with OLT-side amplification[J]. Optics Express, 2019, 27(13):18343-18350.
[40] Wang D D, Wang L Q, Chen X, et al. Construction of irregular QC LDPC codes with low error floor for high speed optical communications[C]//Conference on Lasers and Electro-optics, San Jose, USA, June, 2016:1-2.
[41] Zou D, Djordjevic I B. FPGA-based rate-adaptive LDPC-coded modulation for the next generation of optical communication systems[J]. Optics express, 2016, 24(18):21159-21166.
[42] Yu Q Y, Li Y C, Cheng C X, et al. 50 Gb/s optical transmission system based on 12 GHz receiver assisted with adaptive equalization and LDPC coding[C]//24th Opto-Electronics and Communications Conference and International Conference on Photonics in Switching and Computing. Fukuoka, Japan, July, 2019:1-3.
[43] Ciaramella E. Polarization-independent receivers for low-cost coherent OOK systems[J]. IEEE Photonics Technology Letters, 2014, 26(6):548-551.
[44] Cano I N, Lerín A, Polo V, et al. Flexible D (Q) PSK 1.25-5 Gb/s UDWDM-PON with directly modulated DFBs and centralized polarization scrambling[C]//European Conference on Optical Communication, Valencia, Spain, October, 2015:1-3.
[45] Erkilinç M S, Lavery D, Shi K, et al. Polarization-insensitive single-balanced photodiode coherent receiver for long-reach WDM-PONs[J]. Journal of Lightwave Technology, 2016, 34(8):2034-2041.
[46] Zhang J W, Wey J S, Shi J Y, et al. Single-wavelength 100 Gb/s PAM-4 TDM-PON achieving over 32 dB power budget using simplified and phase insensitive coherent detection[C]//European Conference on Optical Communication, Rome, Italy, September, 2018:1-3.
[47] Altabas J A, Valdecasa G S, Suhr L F, et al. Real-time 10 Gbps polarization independent quasicoherent receiver for NG-PON2 access networks[J]. Journal of Lightwave Technology, 2018, 37(2):651-656.
[48] Jensen J B, Altabas J A, Gallardo O, et al. Quasi-coherent technology for cost efficient high loss budget transmission[C]//Optical Fiber Communications Conference and Exhibition, San Diego, USA, March, 2020:1-3.
[49] Jignesh J, Corcoran B, Schröder J, et al. Polarization independent optical injection locking for carrier recovery in optical communication systems[J]. Optics Express, 2017, 25(18):21216-21228.
[50] Wang Y X, Kasai K, Yoshida M, et al. 320 Gbit/s, 20 G symbol/s 256 QAM coherent transmission over 160 km by using injection-locked local oscillator[J]. Optics Express, 2016, 24(19):22088-22096.
[51] 梁凌寰,宋英雄,林如俭. 基于光梳状谱发生器和注入锁定本地激光器的相干正交频分复用无源光网络系统[J]. 光学学报,2019, 39(9):0906004. Liang L H, Song Y X, Lin R J. Demonstration of coherent orthogonal frequency division multiplexing passive optical network system based on optical frequency comb and injection locking local laser[J]. Acta Optica Sinica, 2019, 39(9):0906004. (in Chinese)
[52] Yi X W, Shieh W, Tang Y. Phase estimation for coherent optical OFDM[J]. IEEE Photonics Technology Letters, 2007,19(12):919-921.
[53] Li J Q, Li L, Tao Z N, et al. Laser-linewidth-tolerant feed-forward carrier phase estimator with reduced complexity for QAM[J]. Journal of Lightwave Technology, 2011, 29(16):2358-2364.
[54] Le S T, Kanesan T, Mccarthy M E, et al. Experimental demonstration of data-dependent pilot-aided phase noise estimation for CO-OFDM[C]//Optical Fiber Communications Conference and Exhibition, San Francisco, USA, March, 2014:1-3.
[55] Bo T W, Huang L C, Chan C K. Common phase estimation in coherent OFDM system using image processing technique[J]. IEEE Photonics Technology Letters, 2015, 27(15):1597-1600.
[56] Ma J J, Li Z X, Xu Y T, et al. Projection histogram assisted common phase estimation algorithm in coherent optical OFDM system[C]//Opto-Electronics and Communications Conference and Photonics Global Conference, Singapore, August, 2017:1-3.
[57] 马俊洁,孙腾雰,李正璇,等. 基于投影直方图的CO-OFDM系统盲相位噪声补偿算法[J]. 光学学报,2018, 38(4):0406001. Ma J J, Sun T F, Li Z X, et al. Blind phase noise compensation algorithm for CO-OFDM system based on projection histogram[J]. Acta Optica Sinica, 2018, 38(4):0406001. (in Chinese)
[58] Li Z X, Li Y, Ma J J, et al. Projection histogram-assisted estimation of common phase error in coherent optical OFDM systems[J]. IEEE Photonics Journal, 2019, 11(3):1-9.