Notes/Answer Question Scenario Summary Keywords © 2003Fiberdyne Labs,Inc. the DWDMchannels(andwavelengths)aredividedamongthesethree,CATV,colorbands. channels aregroupedintothree“color”bands:Blue,PurpleandRed.Thefollowingtableshowshow industry typicallyusesonlychannels19through59.WithintheCableTVindustry,theseC-Band According totheITU'sDWDMGrid,C-Bandincludeschannels1through72.However,CATV optic applications,likeCableTelevision(CATV). Bands areconvenientwaysfordescribingagroupofwavelengths,whichusedinvariousfiber- defined bytheInternationalTelecommunicationUnion(ITU)“Grid,”as1520.25-nmto1577.03-nm. Band) iscenteredat1550-nm.TheC-band,forDenseWavelengthDivisionMultiplexing(DWDM), Fiber-optic wavelengthsaredividedintoseveral“bands.”Forexample,theC-Band(orConventional- Which DWDMchannelsarerepresentedbywhichcolor“band?” Purple andRed. A CableTVproviderasksforDWDMmodule.Thechannelsarespecifiedusingthecolors:Blue, Red channels.Thenarrowsection,whichdividestheandBlue,includesPurple Red. Basically,thelowerhalf,ofC-Band,includesbluechannels.Theupperhalf For fiber-optic,Cable-TVpurposes,the“C-band”isdividedintothreecolor“bands:”Blue,Purpleand Application, CATV,DWDM,Fiber-optics that onebanddoesnotoverlap anotherband. Purple bandisusedasa“guard band.”Aguardbandisarelativelylargeseparation, whichensures channels, intotheaboveRed andBluegroups.Insomeapplications,liketheRed/Blue filter,the Note Or, graphically.... C h # : someofFiberdyne'sDWDM productsusea“Red/Blue”filter.Thisfilterdivides theITUGrid : 59 Channel Numbers 58 57 59 to45 56 35 to19 43 to37 55 54 B 53 L DWDM “Color”BandsforCATVIndustry 52 U 51 E 50 49 48 47 Application Note Wavelengths (nm) 1530.33 to1541.35 46 1549.32 to1562.23 1542.94 to1547.72 www.fiberdyne.com 45 43 P 42 U 41 R 40 P 39 L 38 E 37 35 34 33 CATV ColorBand 32 AN3023 Rev B, Page 31 30 Purple Blue Red 29 R 28 E 27 D 26 25 24 23 22 1 21 of 20 1 19.