Protection of Passive Optical Networks by Using Ring Topology and Tunable Splitters

Pavel Lafata


This article proposes an innovative method for protecting of passive optical networks (PONs), especially the central optical unit – optical line termination (OLT). PON networks are typically used in modern high-speed access networks, but there are also several specific applications, such as in business, army or science sector, which require a complex protection and backup system against failures and malfunctions. A standard tree or star topologies, which are usually used for PON networks, are significantly vulnerable mainly against the malfunctions and failures of OLT unit or feeder optical cable. The method proposed in this paper is focused on forming PON network with ring topology using passive optical splitters. The main idea is based on the possibility of placing both OLT units (primary and secondary) on the opposite sides of the ring, which can potentially increase the resistance of network. This method is described in the article and scenarios and calculations using symmetric or tunable asymmetric passive optical splitters are included as well.

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ITU-T, “G.987.1 - 10-Gigabit-capable passive optical network (XG-PON) systems: Definitions, Abbreviations, and Acronyms,” ITU-T, January 2010. Available

IEEE, “IEEE Standard 802.3av-2009, Amendment 1: Physical Layer Specifications and Management Parameters for 10 Gb/s Passive Optical Networks,” IEEE 802.3av 10G-EPON Task Force. [online], September 2009. Available

C. F. Lam, Passive Optical Networks: Principles and Practice. Academic Press of Elsevier Inc., Burlington, USA. 2007.

P. Lafata, J. Vodrážka, “Application of Passive Optical Network with Optimized Bus Topology for Local Backbone Data Network,” Microwave and Optical Technology Letters. 2011, vol. 53, no. 10, p. 2351-2355.

S. Dong-Min, J. Eui-Suk, K. Byoung-Whi, “A simple passive protection structure in a ring-type hybrid WDM/TDM-PON,” 11th International Conference on Advanced Communication Technology. ICACT 2009, February 2009, p. 447-449.

C. M. Machuca, J. Chen, L. Wosinka, “PON protection architectures achieving total cost reduction,” Conference and Exhibition (ACP) of Communications and Photonics, 2010 Asia, December 2010, p. 707-708.

S. Xia, Q. J. Zeng, J. Wang, H. Zhao, H. Chi, Y. Wang, F. Liu, F., X. Zhu, “Tunable optical splitter technology,” SPIE Proceedings, Vol. 4870-70, SPIE, July, 2002.

P. Lafata, J. Vodrážka, “Návrh pasivních optických sítí s optimálními rozbočovacími poměry,” Elektrorevue. 2010, vol. 13, no. 67, p. 67-1-67-8. Available:

Z. Yun, L. Wen, Ch. Long, X. Qingming, “A 1x2 Variable Optical Power Splitter Development,” Journal of Lightwave Technology, vol. 24, no. 3, March 2006.

X. Tang, J. Liao, H. Li, L. Zhang, R. Lu, Y. Liu, “Design and analysis of a novel tunable optical power splitter,” Chinese Optics Letters, vol. 9, no. 1, January 2011.



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