Conference title, upper and lower case, bolded, 18 point type, centered

Integrated Components for Optical QPSK Transmission
Reinhold Noé (1), Timo Pfau (1), Yakoov Achiam (2), Franz-Josef Tegude (3), Henri Porte (4)
(1) Univ. Paderborn, EIM-E, Warburger Str. 100, D-33098 Paderborn, Germany, noe@upb.de; pfau@ont.upb.de (2) CeLight Israel Ltd., Rotem Industrial Park, Doar Na Arava, Israel, yachiam@celight.com (3) Univ. Duisburg-Essen, Lotharstr. 55, ZHO, LT, D-47048 Duisburg, Germany, Tegude@hlt.uni-duisburg.de (4) Photline Technologies, Bâtiment DF, Route de Gray, B.P. 71025, F-25001 Besançon cedex 3, France, henri.porte@photline.com Abstract: LiNbO3 Z-cut QPSK modulators, LiNbO3 90° hybrids co-packaged with balanced
photoreceiver OEICs and SiGe/CMOS circuits for digital signal processing are being developed as
key components for a 40-Gb/s synchronous QPSK polarization division multiplex transmission
testbed.
2006 Optical Society of America
OCIS codes: (060.1660) Coherent communications; (060.2920) Homodyning
Synchronous quadrature phase shift keying (QPSK) transmission combined with polarization division multiplex is an extremely attractive modulation format for metropolitan area and long haul fiber communication [1−3]. All linear optical distortions (polarization transformations [4], polarization mode and chromatic dispersions) can in principle be equalized without losses in the electrical domain. OSNR performance is superior, and dispersion tolerances are relaxed compared to 40 Gb/s intensity modulation. The European Commission funds in its FP6 under contract 004631 research on “Key components for synchronous optical quadrature phase shift keying transmission”. This “synQPSK” project (http://ont.upb.de/synQPSK) aims to realize all components which are not readily found on the market: LiNbO3 QPSK modulators in the transmitter, LiNbO3 optical 90° hybrids, InP balanced photoreceivers and SiGe/CMOS integrated electronic circuits for signal conditioning in the receiver. Standard DFB lasers are expected to be tolerable for signal and local oscillator lasers due to a carrier recovery concept that requires no phase-locked loop. It shall be implemented in the receiver by analog-to-digital conversion and subsequent CMOS signal processing. The targeted symbol rate is 10 Gbaud which amounts to 40 Gb/s, plus FEC overhead. All components and contributions shall be validated in a testbed (Fig. 1). Currently a QPSK modulator with Z− domain inversion [5] and a 25 GHz bandwidth, optical 90° hybrids [6] reliably co-packaged with photodetector arrays and 10 Gbaud transimpedance amplifiers, and first designs of the electronic components have been developed. We will concentrate on achieved integrated optical component results. These have so far enabled the first real-time QPSK transmission [7]. The planned European „synQPSK“ technology is challenging but tempting to solve several urgent problems of future lightwave communication systems. Due to its high performance we expect a lower cost per bit than for competing technologies. ETX
ERX
Fig. 1. Planned synchronous QPSK polarization division multiplex transmission testbed, with shaded key components. [1] R. Noé, Phase-noise tolerant feedforward carrier recovery concept for baseband-type synchronous QPSK/BPSK receiver, Proc. 3rd IASTED Int. Conf. on Wireless and Optical Communications, Banff, Canada, July 14-16, 2003, ISBN: 0-88986-374-1, pp. 197-201 [2] S. Tsukamoto, D.-S. Ly-Gagnon, K. Katoh, K. Kikuchi, Coherent Demodulation of 40-Gbit/s Polarization-Multiplexed QPSK signals with 16-GHz Spacing after 200-km Transmission, Proc. OFC/NFOEC2005, PDP29, March 6-11, 2005, Anaheim, CA, USA. [3] R. Noé, PLL-Free Synchronous QPSK Polarization Multiplex/Diversity Receiver Concept with Digital I&Q Baseband Processing, IEEE Photon. Technol. Lett., Vol. 17, 2005, pp. 887-889 [4] S. Calabrò et al., An electrical polarization state controller and demultiplexer for polarization multiplexed optical signals, Proc. ECOC 2003, Sept. 21-25, 2003, Rimini, Italy, Th2.2.2 [5] N. Courjal, H. Porte, J. Hauden, P. Mollier, N. Grossard, "Modeling and Optimization of low chirp Mach-Zehnder modulators with an inverted ferroelectric domain section", Journal of Lightwave Technology, Vol. 22, No.5, pp. 1338-1343 (2004) [6] A. Kaplan et al., LiNbO3 Integrated Optical QPSK Modulator and Coherent Receiver, Proc. ECIO 2003, 2-4 April 2003, Prague, Czech [7] T. Pfau et al., Real-time synchronous QPSK transmission with standard DFB lasers and digital I&Q receiver, COTA 2006, CThC5

Source: http://groups.uni-paderborn.de/ont/synQPSK/pdfdata/FIO_components_synQPSK_p04.pdf