Abstract

With the rapid growth of Internet traffic, there can be multiple pairs of bi-directional fibers on a network link. This leads to the need for high-degree reconfigurable optical add/drop multiplexers (ROADMs) in an optical network. However, this high-degree requirement poses new challenges to ROADMs since it is challenging and expensive for a wavelength selective switch (WSS), a key switching component in a ROADM, to expand its size. Therefore, a common strategy is to use small-size WSSs to build a high-degree ROADM. In this paper, we design a novel colorless, partially directionless, and contentionless (CpDC) ROADM architecture, in which the sizes of WSSs can be significantly reduced by partially sacrificing the directionless feature of a ROADM. The partially directionless feature may degrade the switching performance of a ROADM. Thus, to tackle this issue, we also propose an interconnection pattern for the ROADM backplane to effectively connect fiber links and add/drop modules. An analytical model is developed to evaluate the lightpath blocking performance of a single CpDC ROADM. Efficient routing, fiber, wavelength, and add/drop port assignment (RFWPA) algorithms (i.e., the shortest-path-based and waveplane-based algorithms) are also developed for lightpath establishment in an optical network made up of CpDC ROADMs, in which two wavelength selection strategies [i.e., non-interconnection aware (NIA) and interconnection aware (IA)] are further proposed. Simulation studies show that, while these achieve almost the same lightpath blocking performance as conventional CDC ROADMs, CpDC ROADMs are more effective from considerations of cost, insertion loss, and node volume. The waveplane-based RFWPA algorithm with the IA strategy is also found to be the most effective for lightpath provisioning in an optical network made up of CpDC ROADMs.

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Impact of ROADM Colorless, Directionless, and Contentionless (CDC) Features on Optical Network Performance [Invited]

Yongcheng Li, Li Gao, Gangxiang Shen, and Limei Peng
J. Opt. Commun. Netw. 4(11) B58-B67 (2012)

Wavelength Contention-Free via Optical Bypass Within a Colorless and Directionless ROADM [Invited]

Winston I. Way, Philip N. Ji, and Ankitkumar N. Patel
J. Opt. Commun. Netw. 5(10) A220-A229 (2013)

Add/Drop Contention-Aware RWA With Directionless ROADMs: The Offline Lightpath Restoration Case

Pablo Pavon-Marino and Maria-Victoria Bueno-Delgado
J. Opt. Commun. Netw. 4(9) 671-680 (2012)

Experimental demonstration of multi-degree colorless, directionless, contentionless ROADM for 127-Gbit/s PDM-QPSK transmission system

Yohei Sakamaki, Takeshi Kawai, Tetsuro Komukai, Mitsunori Fukutoku, Tomoyoshi Kataoka, Toshio Watanabe, and Yuzo Ishii
Opt. Express 19(26) B1-B11 (2011)

Low-Cost CDC ROADM Architecture Based on Stacked Wavelength Selective Switches

Haining Yang, Brian Robertson, Peter Wilkinson, and Daping Chu
J. Opt. Commun. Netw. 9(5) 375-384 (2017)