pp. 527-542 527 Transmission and distribution of a multichannel AM-VSB TV signal on a single mode optical fiber for CATV videocommunication networks Christian Jean RICHARD * Stdphane HERGAULT * Patrick HARDY * Etienne BONNEAU * Rdgis LEQUEUX * Hubert PRIOUL * Serge BASLE * Abstract First of all, in this paper, we situate and recall the advantage of single mode fiber for transmission of a mul- tichannel AM-VSB TV signal. Then we describe the proto- type of a multichannel transmission system studied under a France T#l~com contract and discuss the experimental results obtained on this system. Today the equipment issued from that study, is in current industrial deve- lopment in order to be soon installed in networks. A few rules are given in terms of range, number of chan- nels per fiber and number of subscribers to help the design of networks. After having identified the system limitations, solutions are proposed to improve the per- formances. Particularly the concept of a AM-VSB optical repeater and the linearity improvement with that proce- dure are shown. We will also discuss the use of 1.54 #m D~ laser and compare the performances at both wave- lengths. The interest of predistortion network to escape from the previously identified linearity constraint is jus- tified. Then the extension of transport network to opti- cal distribution network closer to the subscriber (vrrc) is envisaged. We show how the trade-off between less stringent performances and higher distribution poten- tiality can be handled. At last the interest of external modulation in order to escape from the noise limitation and to extend the coverage of the network at both wave- lengths is discussed. Key words : CATV network, Frequency division multiplexing, Amplitude modulation, Vestigial sideband, Optical telecommunica- tion, Optical fiber transmission, Single mode optical fiber, Prototype, Experimental results, Transmission characteristic, Optical transmitter, Optical receiver. R~sum~ L'article rappelle tout d' abord les avantages apport~s par l'utilisation de la fibre optique unimodale dans les r~seaux de transport et de distribution d'un multiplex fr#quentiel de signaux de tdl~vision modul~s en ampli- tude ?* bande laMrale r~siduelle (MAmLR), puis d~crit et pr#sente les rdsultats expdrimentaux obtenus sur un systdme de transmission optique multicanaux utilisant une diode laser (DFB) ~ 1,3 #m #tudi6 et r#alis~ dans le cadre d'un contrat d'6tude France T~16com. Des solu- tions sont propos~es pour am~liorer les performances en lindariM du rdseau optique. L'inMr~t de la modulation optique externe pour la r6alisation de ce type de r~seau MA/BIR est ~galement abord6. Mots cl~s : Reseaux tdlddistribution, Multiplexage frdquence, Modulation amplitude, Bande lat6rale rdsiduelle, Tdldcommunication optique, Transmission fibre optique, Fibre optique unimodale, Pro- totype, Rdsultat expdrimental, Caractdristique transmission, Emetteur optique, Rdcepteur optique. Contents I. Introduction. II. Expected evolution of the network. III. Main features of the prototype network. IV. Experimental set up. V. Experimental results. VI. Next steps in CATV networks. VII. Conclusion. References (4 ref ). TRANSMISSION D'UN SIGNAL DE TI~LI~VISION MULTICANAL PAR MODULATION D'AMPLITUDE BANDE LATI~RALE RI~SIDUELLE SUR FIBRE OPTIQUE UNIMODALE DANS LES RI~SEAUX DE TI~LI~DISTRIBUTION I. INTRODUCTION During the last 10 years, the optical fiber has never ceased to improve and it has won an immovable place * Thomson-csF/LaboratoiresElectroniques de Rennes, avenue de Belle-Fontaine, F-35510 Cesson-Sevignr, France. 1/16 ANN. T~Lt~COMMUN., 49, n~ 9-10, 1994