1816 JOURNAL OF LIGHTWAVE TECHNOLOGY, VOL. 27, NO. 12, JUNE 15, 2009 Field-Trial Evaluation of Cross-Layer Effect Caused by All-Optical Wavelength Converters on IP Network Applications M. L. F. Abbade, J. D. Marconi, R. L. Cassiolato, V. Ishizuca, I. E. Fonseca, and H. L. Fragnito, Member, IEEE Abstract—Future Internet infrastructure will require the utiliza- tion of new all-optical devices able to enhance the use of fiber ca- pacity. Nevertheless, before deploying such devices, it is necessary to test them under conditions similar to the ones of commercial net- works and to evaluate their impact on real-world applications. In this work we investigate the performance of a tunable fiber four- wave mixing all-optical wavelength converter (AOWC) on a video- streaming carried through a field-trial network. This analysis is performed by measuring the packet-error rate (PER) degradation caused by the AOWC for different wavelength separations between the input and output optical carriers. To the best of our knowl- edge, this is the first time that such a cross-layer effect is systemat- ically evaluated for an AOWC. A dynamic polarization controller was successfully used to prevent the FWM efficiency variations that were caused by the changes in the state-of-polarization of the video signal. Our results show that the AOWC introduced a max- imum power penalty of 2.5 dB for wavelength separations of up to 12 nm. We also find that such a penalty is related to the optical signal-to-noise ratio degradation induced by the converter. Index Terms—All-optical wavelength converters (AOWC), cross-layer effect, transparent optical network (TON), wavelength division multiplexing (WDM). I. INTRODUCTION I N CASE TRAFFIC continues to increase at the present rate [1], the traditional electronic approach used in core routers may soon become a barrier for the Internet growth. This happens not only because the required switching speed may turn to be higher than the one that can be supplied by elec- tronics, but also because of the excessive amount of energy that would be consumed by these routers [1]. Transparent optical networks (TONs) based on wavelength division multiplexing Manuscript received December 01, 2008; revised March 21, 2009. First published April 24, 2009; current version published June 05, 2009. This work was supported by FAPESP and CNPq under processes 03/08320-2, 03/08196-0, 06/50911, 08/57857-2, and 574017/2008-9. M. L. F. Abbade, R. L. Cassiolato, and V. Ishizuca Teles are with the School of Electrical Engineering, PUC-Campinas, Rod. D. Pedro I- km 136, Campinas, SP, 13086-900, Brazil (e-mail: abbade@puc-campinas.edu.br; renatolcas@gmail.com; ishizuca@gmail.com). J. D. Marconi and H. L. Fragnito are with the Optics and Photonics Re- search Center, Unicamp-IFGW, Campinas, SP, 13083-970, Brazil (e-mail: jd- marconi1@gmail.com; jdmarconi1@gmail.com). I. E. Fonseca is with the School of Computer Science, Federal University of Semi-Arid Region, Mossoró-RN 59.625-900, Brazil (e-mail: iguatemi@ufersa. edu.br). Color versions of one or more of the figures in this paper are available online at http://ieeexplore.ieee.org. Digital Object Identifier 10.1109/JLT.2009.2021002 (WDM) technology emerge as an attractive solution for solving both of these problems [2], [3]. However, the efficient use of the full capacity that is provided by TONs depends on factors such as: 1) optical switching tech- nology; 2) traffic distribution; 3) design of network architec- ture; and 4) deployment of new all-optical devices. The first of these factors concerns the choice of the optical switching tech- nique that should be utilized. At a first sight, it seems convenient to reproduce the high-granularity strategy that is presently im- plemented by Internet routers and to perform optical switching in a packet-by-packet basis. Nevertheless, the technology re- quired by this optical packet-switching (OPS) [4] approach is not mature yet and its practical viability remains controversial [5] even after several years of research on this field. Another possibility is the use of optical circuit-switching where a con- nection between end clients is established/terminated just be- fore/after data transmission. This approach may be called op- tical burst wavelength routing (WR) [6]. Optical burst switching (OBS) has been also proposed as a compromise between OPS and WR [7] but presently WR technology is the only one that is mature enough to be used commercially [3]. Thus, in the re- mainder of this paper we will consider that the implementation of TONs follows the WR approach. The proper utilization of network capacity will also be deeply affected by traffic distribution. Typically, the network manage- ment system (NMS) must use some routing and wavelength as- signment (RWA) algorithm to either minimize the amount of connections that may be blocked or to maximize the number of network connections at any moment [7]. More sophisticated al- gorithms should also take into account the effects of physical impairments on some kind of metric. In fact, these impairments aware RWA (IA-RWA) algorithms [8] should take into account not only the degradations caused during fiber propagation but also those ones originated from the action of optical devices. In [9] and [10] IA-RWA algorithms were proposed to take into ac- count the influence of four-wave mixing (FWM) on the bit-error rate (BER) of the channels of a WDM network. In [11] and [12], IA-RWAs were developed for considering the deterioration im- posed by chromatic dispersion and polarization-mode disper- sion on the Q-factor of the signals in a TON. The influence of the amplified-spontaneous emission (ASE) noise of optical amplifiers on the BER of signals in a WDM network was pre- sented in [13] and [14]. The effect of ASE noise on the optical signal-to-noise ratio (OSNR) was reported in [15]. Generally speaking, IA-RWA algorithms are essential to prevent traffic 0733-8724/$25.00 © 2009 IEEE Authorized licensed use limited to: UNIVERSIDADE ESTADUAL DE CAMPINAS. Downloaded on June 23, 2009 at 14:37 from IEEE Xplore. Restrictions apply.