ActiveopticalwaveguidesbasedonEr-andEr/Yb-doped silicateglasses G.C.Righini a, * ,S.Pelli a ,M.Brenci a ,M.Ferrari b ,C.Duverger c , M.Montagna c ,R.Dall'Igna d a Optoelectronics and Photonics Department, IROE-CNR, via Panciatichi 64, I-50127 Firenze, Italy b Consiglio Nazionale delle Ricerche CeFSA, Centro Fisica Stati Aggregati, via Sommarive 14, I-38050 Povo±Trento, Italy c Dipartimento di Fisica and INFM, Universit  a di Trento, via Sommarive 14, I-38050 Povo±Trento, Italy d Stazione Sperimentale del Vetro, via Briati 10, I-30141 Murano Venezia, Italy Abstract ThegrowinginterestfortheuseofintegratedopticalIO)ampli®ersinoptical®bretelecomsystemshasledtodepth search for ever better rare-earth-doped glassy materials. In the present paper we report some properties of a set of Er 3 =Yb 3 -dopedsoda-limesilicateglasses.Severalbatcheswereprepared,allwiththesamebasemol%composition 73SiO 2 ±1Al 2 O 3 ±0:4P 2 O 5 ±14Na 2 O±0:6K 2 O±11CaO)containingEr 2 O 3 0.32±0.48%)andYb 2 O 3 0.63and0.78%).The resultingglasseswerecutintorectangularplatesabout1mmthick,andonesurfacewasopticallypolished.Planarand channel waveguides were subsequently obtained in these plates by Ag  ±Na  ion-exchange. Spectroscopic analysis showedthatthe¯uorescenceemissionpeakforallthesampleswasobservedat1532  1nm,withafull-widthathalf- maximumequalto19nm.MeasurementsofthelifetimeofthemetastablestateofEr 3 wereperformeduponexcitation bylaserpumpsat514.5and980nm,andtimesoftheorderof7msweremeasuredinmostsamples.Theintensityofthe up-conversion¯uorescencewaslessinEr 3 =Yb 3 co-dopedglassesthaninEr 3 -dopedones.Preliminarymeasurements ofthetransmittedpowerat1540nminchannelwaveguidesmadeintheglassdopedwithnominal0.32mol%ofEr 2 O 3 havecon®rmedtheirpotentialofachievingopticalgain;infact,asignalenhancementinternalgain) >1dB/cmwas measuredwithmorethan1mWinputsignal. Ó 2001ElsevierScienceB.V.Allrightsreserved. PACS: 42.70.C;42.82E;78.55 1. Introduction Recently,agrowingactivityhasbeenconcerned withthegoalofachievingopticalgaininEr-doped opticalwaveguides[1],havinginmindthesingle- chiprealisationofintegratedopticIO)ampli®ers andlasers[2],possiblycombinedwithothercom- ponents [3]. As an example, a critical device, es- peciallyinlocalareanetworks,isalosslesssplitter for signal distribution to a number of outputs, which can be realised in IO as a branch coupler e.g., 1  16) combined with an optical ampli®er. Forcostreasons,itwouldbedesirabletofabricate such a lossless coupler in a glass substrate [4]. However,whileopticalampli®cationatthewave- lengthof1.5 lmisamaturetechnologyforoptical ®bresEDFAshavebeencommerciallydeveloped duringthelastfewyears),thesameisnottruein IOstoourknowledge. JournalofNon-CrystallineSolids2842001)223±229 www.elsevier.com/locate/jnoncrysol * Corresponding author. Tel.: +39-55 423 5239; fax: +39-55 412878. E-mail address: righini@iroe.®.cnr.itG.C.Righini). 0022-3093/01/$-seefrontmatter Ó 2001ElsevierScienceB.V.Allrightsreserved. PII:S0022-309301)00406-9