Vol. 58 n°11-12, november-december 2003

Optical communications (2) Transmission systems and networks

 

Guest editors : Yves JAOUËN* and Michel JOINDOT**

*GET/Télécom Paris

**France Télécom R&D

 

 

European IST-programme roadmap for optical communications generated by the OPTIMIST thematic network

Ann ACKAERT¹, Piet DEMEESTER¹, Paul LAGASSE¹, Christina POLITI², Mike O'MAHONY², Tommy BERG³, Bjarne TROMBORG³, Juergen SANITER⁴, Erwin PATZAK⁴, Sathya RAO⁵, Paul VOGEL⁵, Christophe MINOT⁶, Didier ERASME⁶

1. IMEC Vzw, INTEC, Kapeldreef 75, B-3001 LEUVEN, Belgium; e-mail: ann.ackaert@intec.rug.ac.be.

2. University of Essex, Photonic Networks Laboratory, Dpt of Electronic Systems Engineering, Wivenhoe Park,COLCHESTER Essex CO4 3SQ, United Kingdom

3. DTU, Research Center COM, Building 345V, DK-2800 KGS LYNGBY, Denmark

4. HHI Abt ON, Einsteinufer 37, 10587 BERLIN, Germany

5. Telscom, Sandrainstr. 17, 3007 BERN, Switzerland

6. GET/Télécom Paris, Dpt Comelec; 46, rue Barrault 75634 PARIS cedex 13, France

 

Abstract:  On the basis of European IST project results in the field of photonics, the OPTIMIST thematic network has produced a roadmap for optical communications. This work is described in the present article which provides scenarios for the evolution of the optical network in the coming 10 years. Predictable developments in optical components, sub-systems and systems and their consequences on the architecture and performances of the networks are analysed. Specific interest is focused on the various parts of the network structure namely the access, the metropolitan area, the wide area and the global networks. Technical documents elaborated by the OPTIMIST consortium and minutes from IST workshops can be found on the website http://www.ist-optimist.org/.[1]. They constitute a main source for further information.

Key words: Optical telecommunication, Research program, Futurology, European union, Scenario, Telecommunication network, Access network, Metropolitan area network, Wide area network, Evolution,  Optical component, Optical fiber transmission.

OPTIMIST = Optical Technologies in Motion for the IST Programme.

 

 

Optical communication and fiber design

Pascale NOUCHI*, Bruno DANY*, Jean-Florent CAMPION*, Louis-Anne de MONTMORILLON*, Pierre SILLARD*, Alain BERTAINA*

* Alcatel Cable, 53 rue Jean Broutin, 78700 Conflans Saint Honorine, France e-mail: pascale.nouchi@alcatel.fr

 

Abstract: Optical fiber has evolved from a not-so-transparent glass tube to an extraordinarily efficient transmission medium. It is now acknowledged as a central element of modern telecommunication being part of the whole optimization process to further improve transmission system performance and cost. In this paper, we briefly introduce transmission system optimization problematics as well as key fiber characteristics. We then review the elements of fiber design for optimized optical communication networks, including metropolitan, long and ultra-long haul applications and show how fibers have evolved over the last ten years to keep pace with more and more demanding requirement of transmission system.

 

Key words: Optical telecommunication, Optical fiber transmission, Optical fiber, System performance, Optimization, Metropolitan area network, Long distance transmission,Wave dispersion.

 

 

Optical Fiber Amplification Technology

Dominique BAYART*

*Alcatel Research and Innovation, route de Nozay, 91491 Marcoussis CEDEX, France ; Dominique.Bayart@alcatel.fr

 

Abstract :  This part aims at giving keys to understand why erbium-doped fiber amplifiers (EDFA) have revolutionized signal transmission techniques and how they can complement with Raman amplification in next generation systems. A first part is dedicated to physics basics of EDFA followed by the description of the system requirements for both terrestrial and submarine applications. Their related characteristics and second-order effects seen as possible limitations in systems will be reviewed. Future developments based on cladding-pumping or operation in the L-band and benefit of using Raman distributed amplification will be analyzed. Finally, amplification solutions dedicated to operation in new bands will be discussed as well.

 

Key words: Optical telecommunication, Optical fiber, Optical amplifier, Lanthanide doped fiber, Erbium, Stimulated Raman scattering, Wavelength division multiplexing, State of the art, System performance, Spectral window.

 

 

 High power cladding-pumped Er3+/Yb3+ fiber amplifiers: technologies, performances and impact of nonlinear effects

Yves JAOUËN*, Sylvain BORDAIS**, Elena OLMEDO*, Gabor KULCSAR**, Jean-Yves ALLAIN**

* GET/Télécom Paris ; Unité de recherche associée au CNRS (UMR 5141) ; 46 rue Barrault, 75634 Paris Cedex 13, France

** Keopsys SA ; 21 rue de Broglie, 22300 Lannion, France.

 

Abstract: Yb3+-sensitized Er3+-doped fibers are attracting increasing interest because of the high achievable performances, such as high gain and pump efficiency. High output power can be obtained from a double clad (DC) Er3+/Yb3+ co-doped fiber pumped with broad area high power pump laser diodes. The principle of amplification in this kind of co-doped fibers is presented in this paper. Different solutions for the injection of pump power in the 1st-cladding have been described. The energy transfer mechanism in a Er3+/Yb3+ co-doped system including cooperative-upconversion process is explained. Gain and absorption properties of DC fibers have been determined experimentally and inserted in a theoretical amplifier model. Good agreement between measurements and modelling has been obtained. Hybrid Er3+-Er3+/Yb3+ amplifier architectures are suitable to obtain + 30 dBm output power. The gain bandwidth is in the 1535-1565 nm range for single wavelength operation. A spectral gain flatness is observed in a reduced C-band WDM operation (i.e. 1545-1565 nm) without gain-flattening filter. Nonlinear effects such as the optical Kerr effect or the stimulated Brillouin scattering can be observed in high power amplifiers due to the high output peak power confined in the fiber core. These two nonlinear phenomena have been investigated for different high power amplifier configurations. Numerical modelling have also confirmed the observed signal distortions.

Key words: Optical telecommunication, Optical amplifier, Optical fiber, Lanthanide doped fiber, Erbium, Ytterbium, Non linear effect, Optical pumping, Optical fiber cladding, Power amplifier, Modeling, Kerr effect, Stimulated Brillouin scattering, Four wave mixing.

 

 

Ultra-fast quantum-well saturable absorber devices and their application to all-optical regeneration of telecommunication optical signals

Jean-Louis OUDAR¹ Guy AUBIN¹, Juliette MANGENEY², Slimane LOUALICHE³, Jean-Claude SIMON⁴, Alexandre SHEN⁵, Olivier LECLERC⁵

1. Laboratoire de Photonique et de Nanostructures (CNRS-UPR20) route de Nozay, 91460 Marcoussis, France.

2. Institut d'Electronique Fondamentale (CNRS - UMR 8622), Bât. 220, Université Paris-Sud, 91405 Orsay Cedex, France.

3. Laboratoire de Physique du Solide, INSA de Rennes, 20 avenue des Buttes de Coësmes 35043 Rennes Cedex, France.

4. Laboratoire d'Optronique (CNRS- UMR 6082), ENSSAT, 6 rue de Kerampont, 22305 Lannion Cedex, France.

5. Alcatel R&I, route de Nozay, 91460 Marcoussis, France.

 

Abstract:  We review recent advances in the investigation of vertical cavity saturable absorber devices and their use for the all-optical regeneration of telecommunication signals in ultralong- haul transmission systems. Such devices are polarization-insensitive and operate as fully passive nonlinear optical elements. Two approaches for obtaining fast recovery absorber materials are described, relying upon ion irradiation or upon iron doping. The vertical microcavity devices are designed so as to optimize the switching contrast and the operating power. Their functional behaviour as extinction ratio amplifiers has been characterized and their optimal operating conditions have been determined. The potential application of these devices to all-optical regeneration has been investigated through numerical simulations and fully demonstrated in several long-distance transmission loop experiments, with results obtained at 10, 20 and 40 Gbit/s, showing significant improvements in system haul or operational margins. A four-channel fibered module has also been fabricated, as a perspective towards the development of wavelength division multiplexing (WDM) saturable absorber modules.

Key words: Optical telecommunication, Regeneration, Saturable absorber, Quantum well, Semiconductor device, Crystal defect, Doping, Cavity, Microelectronic fabrication, Characterization, Optical component, Modeling, Experimentation.

 

 

All optical regeneration techniques

Jean-Claude SIMON*, Laurent BRAMERIE*, Frédéric GINOVART*, Vincent RONCIN*, Mathilde GAY*, Sylvain FEVE*, Elodie LE CREN*, Marie-Laure CHARES*

* Laboratoire d'Optronique, CNRS UMR 6082 ; Groupement d'Intérêt Scientifique foton ; ENSSAT/Université de Rennes 1, 6 rue de Kerampont, F22305 Lannion, France

 

Abstract:  Basic principles of all-optical signal regeneration are presented, and main state-of-art techniques are reviewed. Optical fiber and semiconductor based devices are addressed, and some recently reported 2R and 3R signal regeneration experiments are discussed.

 

Key words: Optical telecommunication, Optical fiber transmission, Regeneration Optical component, Long distance transmission, Repeater, Synchronizer, Non linear optics, All optical technology.

 

 

State of the art and future of WDM transmission

Michel JOINDOT*

* France Telecom R&D, Technopole Anticipa, 2 av. Pierre Marzin 22307 Lannion, France

 

Abstract:  After briefly recalling the recent history of optical communication, this paper describesthe structure of a WDM system, the critical parameters involved in its design, the different degradations which the transmitted signal suffers from, the state of the art and the future evolutions of WDM transmission technology. Some recent results are given to illustrate the best results obtained in the research laboratories.

 

Key words: Optical telecommunication, Wavelength division multiplexing, State of the art, Review, Background noise, Signal distortion, System performance, Optical amplifier, Optical fiber transmission.

 

 

Design of multi-terabit/s terrestrial transmission systems facilitated by simple analytical tools

Sébastien BIGO*, Yann FRIGNAC*, Jean-Christophe ANTONA*, Gabriel CHARLET*

*Alcatel Research and Innovation, Route de Nozay 91460 Marcoussis, France

 

Abstract:  For 30 years, the capacity distance product of lightwave communication systems has continuously doubled every 16 months, to reach more than 10 Pbit/s.km in 2002. Along with this growth, the complexity of system engineering has increased as linear and nonlinear transmission impairments have become more stringent. Dispersion management is widely accepted as a powerful technique to mitigate some of them, but requires numerous experiments or time-consuming numerical simulations to be performed optimally. We exhibit two analytical rules that provide meaningful insight on this matter. Then we show how these rules helped us to improve the transmission distance of a recent 5 Tbit/s transmission experiment from 1,200 km to 1,500 km.

 

Key words: Optical telecommunication, Optical fiber transmission, Wavelength division multiplexing, Non linear optics, Optical amplifier, Lanthanide doped fiber, Erbium, Stimutaled Raman scattering, Telecommunication network, Analytical method,Wave dispersion, Non linear effect, System performance, Experimentation.

 

 

On the designing of densely dispersion-managed optical fiber systems for ultrafast optical communication

Patrice TCHOFO DINDA*, Alexis LABRUYERE*, Kaliyaperumal NAKKEERAN **, Julien FATOME*, Alain Brice MOUBISSI*, Stéphane PITOIS*, Guy MILLOT*

* Laboratoire de Physique de l'Université de Bourgogne, Unité Mixte de Recherche CNRS n°5027, Faculté des Sciences Mirande. 9 Avenue A. Savary, B.P. 47 870, 21078 Dijon, France

** Present address: Photonics Research Center and Department of Electronic and Information Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.

 

Abstract:  We present some theoretical and experimental results which suggest the possibility of constructing a non-empirical methodology of designing optical transmission systems with ultra high bit-rate per channel. Theoretically, we present an average dispersion decreasing densely dispersion-managed (A4DM) fiber system, which exhibits many advantages over the densely dispersion-managed fiber system, such as the possibility of transmitting chirp-free Gaussian pulses at 160 Gbit/s per channel over transoceanic distances, with a reduced energy and minimal intra-channel interaction. Experimentally we present generation of a 160-GHz picosecond pulse train at 1550 nm using multiple four-wave mixing temporal compression of an initial dual frequency beat signal in the anomalous-dispersion regime of a non-zero dispersion shifted fiber. A complete intensity and phase characterization of the pulse train by means of a frequency-resolved optical gating technique is achieved, showing generation of transform-limited pedestal-free Gaussian pulses.

 

Key words: Optical telecommunication, Optical fibre transmission,Wave dispersion, System design, High rate, Ultrashort pulse, Four wave mixing, Stimulated Raman scattering, Non linear equation, Theoretical study, Experimental result, Long distance transmission, Pulse generator.

 

 

Optics: finding the best fit in telecom transport networks

Amaury JOURDAN*

* Alcatel Research and Innovation, Route de Nozay, F-91460 Marcoussis, France ; Amaury.Jourdan@alcatel.fr

 

Abstract:  This paper aims at looking beyond the gloomy current market evolution of the optical industry. Based on an analysis of the telecom transport market evolution (metropolitan as well as backbone), taking benefit of very significant technological breakthroughs in optics in recent years, this paper will suggest promising, yet pragmatic applications in telecom transport networks where optics will play a significant role beyond pure optical transmission.

 

Key words: Optical telecommunication, Telecommunication network, Metropolitan area network, Wide area network, All optical technology, Technical progress, Futurology.

 

 

Optical networking in CESNET2 gigabit network

Jan RADIL *, Leos¡ BOHÁC¡ *,**, Miroslav KARÁSEK *,***

* CESNET, a.l.e., Zikova 4, Prague, Czech republic, jan.radil@cesnet.cz

** Czech Technical University, Technika 2, Prague, Czech republic.

*** Institute of Radio Engineering and Electronics, Chaberska 57, Prague, Czech republic

 

Abstract:  This paper describes testing, numerical simulations and deployment of advanced opticaltransmission technologies such as optical amplifying and wavelength-division multiplexing in CESNET2 gigabit production network. Practical results are described and future goals are discussed as well.

 

Key words: Optical telecommunication, Telecommunication network, Networking, Optical fibre transmission, Optical amplifier, Lanthanide doped fiber, Stimulated Raman scattering, Long distance transmission, High rate.

 

 

Space applications of optical communications

Emmanuel SEIN*, Gilles PLANCHE*, Bernard LAURENT*, Jean-Pierre BOUZINAC**, Gotthard OPPENHAUSER***, Toni TOLKER-NIELSEN***

* EADS-ASTRIUM ; 31, avenue des Cosmonautes - 31402 Toulouse, France.

**ONERA-DOTA ; CERT, 2, avenue E. Belin - 31000 Toulouse, France.

*** European Space Agency, ESA-ESTEC, Keplerlaan 1 - 2200 AG Noordwijk, The Netherlands.

 

Abstract: Optical communication in Space is now a reality. In this paper we present the recent developments that were undertaken in Europe for this application. We first describe the different missions where optical communications are useful: link between two geostationary satellites (GEO-GEO), Data Relay Mission (LEO-GEO) and High Data Rate Satellite Constellation Network. Then we detail the different candidate laser technologies from the most straightforward technologies that have been developed for optical fiber applications ( l=1.55 µm) and 0.8 µm technology based on Silicon detector to the recent developments based on high power fiber amplifiers. In the last chapter we describe the SILEX (Semi conductor Intersatellite Link Experiment) program which performs optical communication between SPOT4 Earth observation satellite (CNES) and ARTEMIS (ESA). The excellent results based on 0.8 µm laser diode technology are considered to be a major milestone in optical intersatellite communication

Key words: Optical telecommunication, Space application, Inter satellite link, Data relay, Geostationary satellite, LEO satellite, Optical component, System architecture, Experimental result, Research programme.

 

 

Direct-Sequence Code Division MultipleAccess: from radio communications to optical networks

Mounia LOURDIANE*, Philippe GALLION*, Robert VALLET*

* GET/Télécom Paris, Dpt comelec, UMR 5141 du CNRS - 46, rue Barrault 75634 Paris Cedex 13

 

Abstract:  A direct sequence optical code division multiple access technique is investigated. This paper introduces, first, the principles definitions of Code Division Multiple Access in radio communications. After that, the performances of Optical Code Division Multiple Access are evaluated in association with a realistic amplified optical channel model. To determine the performances obtained by this combination, different detection methods are investigated in an Optical CDMA system. Threshold and multi-user detections are developed in association with Optical Orthogonal Codes: OOC and Prime Sequences: PS, specially designed to be adapted to fiber optic channel.

 

Key words: Code division multiple access, Radiocommunication, Direct sequence spread spectrum, Optical telecommunication, Optical fiber transmission, Gaussian channel, Amplification, Coding, Background noise, Signal detection, Error rate.