476 JOURNAL OF LIGHTWAVE TECHNOLOGY, VOL. 28, NO. 4, FEBRUARY 15, 2010 Microring-Resonator-Assisted, All-Optical Wavelength Conversion Using a Single SOA and a Second-Order Si N –SiO ROADM Leontios Stampoulidis, Student Member, IEEE, OSA, Dimitris Petrantonakis, Christos Stamatiadis, Efstratios Kehayas, Member, IEEE, OSA, Paraskevas Bakopoulos, Christos Kouloumentas, Panagiotis Zakynthinos, Konstantinos Vyrsokinos, Ronald Dekker, Member, IEEE, and Edwin J. Klein Abstract—We present the first microring-resonator-assisted wavelength converter employing a semiconductor optical amplifier and a tunable, Si N –SiO microring-resonator-reconfigurable optical add–drop multiplexer. We demonstrate inverted, nonin- verted, and wavelength-division-multiplexing-enabled wavelength conversion with low power penalties. Index Terms—Microring resonators, optical fiber communica- tion, optical packet switching, optical signal processing, photonic integration, reconfigurable add–drop multiplexers, semiconductor optical amplifiers (SOAs), wavelength converters. I. INTRODUCTION P ENETRATION of photonic switching subsystems into next generation core routers is a promising path for solving scalability issues of today’s electronic carrier routing systems [1]. Specifically, these new photonic routers will be called to: 1) drastically reduce the power dissipation of a single rack from its maximum value today, being 10 kW, down to a few hundreds of watts; 2) squeeze more than 1 Tb/s of throughput in a single rack of equipment; 3) scale gracefully to Pb/s capacities keeping down cost, footprint, and power consumption. In order to achieve these challenging advancements, robust micro/nanophotonic integration concepts and technologies need to be developed. These techniques will need to provide the necessary high degrees of compactness and cost effectiveness Manuscript received April 30, 2009; revised July 30, 2009. First published August 18, 2009; current version published February 01, 2010. This work was supported in part by the European Commission through Project ICT-BOOM (FP7-224375) under the Seventh Framework Programme and by the Dutch Gov- ernment under the Freeband BB Photonics project BSIK 03025. L. Stampoulidis, D. Petrantonakis, C. Stamatiadis, E. Kehayas, P. Bakopoulos, C. Kouloumentas, P. Zakynthinos, and K. Vyrsokinos are with the Photonics Communications Research Laboratory, Department of Electrical and Computer Engineering, National Technical University of Athens, GR-15773 Athens, Greece (e-mail: lstamp@mail.ntua.gr, lstamp@cc. ece.ntua.gr; petranto@mail.ntua.gr; cstamat@mail.ntua.gr; ekeha@mail. ntua.gr; pbakop@mail.ntua.gr; ckou@mail.ntua.gr; zakynth@mail.ntua.gr; kvyrs@cc.ece. ntua.gr). R. Dekker is with LioniX BV, 7500 AE Enschede, The Netherlands, and also with the XiO Photonics BV, 7500 BG Enschede, The Netherlands (e-mail: r.dekker@lionixbv.nl). E. J. Klein is with Xio Photonics BV, 7500 BG Enschede, The Netherlands (e-mail: e.j.klein@xiophotonics.com). Digital Object Identifier 10.1109/JLT.2009.2030143 that will enable the implementation of photonic routing archi- tectures [2]. Fig. 1 shows the basic architecture of a photonic packet-switched wavelength router. An electronic control plane is employed for processing headers and an optical routing plane for switching IP packets in the optical domain. The “heart” of the photonic router is the wavelength routing stage that consists of all-optical wavelength converters (AOWCs) connected to an arrayed waveguide grating router (AWGR). These components effectively form an optical backplane that can efficiently route packet traffic at high data rates. The realization of a chip-scale wavelength routing plane has stimulated intensive photonic integration efforts, with the passive part (AWGR) being the first target in the development queue. Multiport AWGRs supporting up to 40 wavelength chan- nels and consuming approximately 17 W have been recently fabricated using either monolithic InP [3] or silica-on-silicon [4] photonic integration. The success in developing compact and low-power-consuming switching fabrics has soon turned the focus on the active core part of the wavelength router—the all-optical wavelength converters (AOWCs). The realization of large-scale photonic routers would require scalable and power efficient AOWCs and R&D investments have stimulated com- ponent-oriented research within the European Union (EU) and the U.S. research projects. In this context, Defense Advanced Research Projects Agency (DARPA) funded project IRIS has presented a 2 8 wavelength switch hosting a dual monolithic InP AOWC and two multiwavelength lasers [3]. In the same line, EU-funded project IST-MUFINS has utilized silica-on-sil- icon hybrid integration to provide a photonic chip that hosts four 40 Gb/s AOWCs and consumes 12 W [5]. Recently, an array of eight monolithic InP AOWCs that offers a total chip throughput of 320 Gb/s in a few micrometers square was presented [6]. In all these demonstrations, the AOWCs have been implemented as semiconductor-optical-amplifier-based Mach–Zehnder interferometers (SOA-MZIs) that employ two active components (SOAs) per AOWC, increasing overall active component count, power consumption, and imposing thermal management requirements. From a system level point of view, the SOA-MZI AOWCs operate in a differential “push–pull” mode to operate at a maximum data rate of 40 Gb/s, requiring precise temporal alignment and power level adjustment be- tween “push” and “pull” pulses. In order to enable even larger and faster photonic integrated AOWC devices, power consumption, thermal crosstalk, and heat dissipation need to be further reduced. The first step is to 0733-8724/$26.00 © 2010 IEEE