T-25e, T-39 & T-66. G657 fibres and how to splice them. TA036DO th June 2011

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1 T-25e, T-39 & T-66 G657 fibres ad how to splice them TA036DO th Jue 2011 What is G657 fibre? G657 is a ew class of sigle mode fibre which ca be bet more severely the ormal G652 sigle mode without losig the sigal it s carryig. It s desiged for use i Fibre to the Home applicatios. The ITU defies 4 classes of G657 fibre as below. G657A1 10mm miim bed radius, other specs as G652 G657A2 7.5mm miim bed radius, other specs as G652 G657B2 7.5mm miim bed radius, other specs may deviate from G652 G657B3 5mm miim bed radius, other specs may deviate from G652 I smary a G657A fibre is like a G652D fibre but with improved bedig characteristics. G657B fibres have improved bedig characteristics ad are allowed to deviate from some G652D specificatios, such as PMD ad Chromatic Dispersio. Sometimes these fibres are all called BIF or Bed Isesitive Fibre How does G657 fibre work? To meet the G657A1 specificatio requires miimal chages to a G652 desig, so G657A1 fibres ca be very similar i structure to G652 fibres ad ca usually be spliced usig a stadard G652 SMF program. To meet the other G657 specs, the fibre either eeds a differet shape core to G652, or some additioal structure aroud the core to keep the light i the core whe the fibre is bet. To date there have bee 4 commercially available desigs of G657 fibre... Tall / thi core Trech aroud the core - also called Trech Assisted Fibre Trech ad rig aroud the core - also called Rig Assisted Fibre Voids aroud the core also called Void Assisted Fibre If you could see the refractive idex profiles of these fibres they d look somethig like the diagrams below... G652 refractive idex profile G657 Tall / Thi type

2 G657 Trech type G657 Trech / Rig type G657 Void Assisted type Who makes these G657 fibres? Sitomo pioeered the desig of Bed Isesitive fibres usig a profile with a tall ad very thi core. Our desig, called Pure Access Ultra, was lauched i Japa i It s o loger produced ad you re ulikely to fid ay i Europe. It has a much smaller MFD tha a typical G652 fibre. The MFD mismatch whe it s joied to G652 gives quite high isertio loss so it s o loger cosidered practical to use. Desig Producer G657A1 G657A2 G657B2 G657B3 Sitomo Pure Access Tall / thi core Corig ClearCurve XB OFS AllWave FLEX Prysmia CasaLite Sitomo PureAccess-R5 Trech oly Draka Bedbright Bedbright-XS Bedbright-Elite Corig ClearCurve LBL Corig ClearCurve ZBL Trech & rig OFS EZ-Bed Voids Prysmia CasaLite-Plus CasaLite-Xtreme What are the special problems splicig these fibres? Geeral issues o The G657B fibres are ot perfectly MFD matched with G652 SMF. Typically their MFD at 1310m is a little smaller tha the MFD of a G652 fibre. So whe a G657B is spliced to a G652 there is always some extra isertio loss due to the MFD mismatch. o I a G652 fibre the distributio of power i the fibre (the mode profile) closely follows a Gaussia distributio. I the G657 fibres the light trasmissio path is differet ad the mode profile may be o-gaussia. This meas there ca be some mode profile mis-match whe G657 fibres are spliced to G652 fibres. This ca create extra isertio loss, i additio to extra isertio loss created by MFD mis-match.

3 o o The refractive idex of the pure silica glass used to make a fibres claddig is icreased or decreased by addig dopat materials. Geerally Germai (Ge) is used to raise the idex (to make the core) ad Fluorie (Fl) is used to reduce the idex (to make a trech). Additio of dopats to the pure Silica ca chage the meltig poit of the glass so these fibres may have a differet meltig poit to G652 fibres. Makig a Arc Test will compesate for this. These are ew fibre desigs which are still evolvig. It s possible they may chage i the future. See the sectio o splicig these fibres with a T-39 below. Splicig G657 fibres o a fixed v-groove splicer o These splicers caot see the core. They do t care that the core is differet to a G652 fibre. Choose the SMF Stadard program, make a Arc Test ad start workig. Splicig G657 fibres o a core aligig splicer o The splicer eeds to be able to see the core to do a core aligmet. Splicers view fibres by lookig through the side of the fibre. If the fibre has extra structure aroud the core it ca shield or distort the core image, or make it difficult for the splicer to fid the correct core focus positio. See the pictures below for examples of how these fibres look o a T-39. Draka BedBright XS (Trech assisted type G657A2 ) spliced to G652 Left fibre: Draka BedBright XS Right fibre: G652 SMF

4 Draka BedBright Elite (Trech assisted type G657B3 ) spliced to G652 Left fibre: BedBright Elite Right fibre: G562 SMF Draka BedBright XS spliced to BedBright Elite (Trech Assisted G657A2 to G657B3) Left fibre: BedBright XS Right fibre: BedBright Elite

5 OFS EZ-Bed (Trech/Rig Assisted type G657B3) spliced to SMF Left fibre: EZ-Bed Right fibre G652 The rig i the EZ-Bed fibre completely shields the core. So for Core aligmet the splicer is actually aligig o the cetre of the rig. OFS have cofirmed that the rig ad the core are close to perfectly cocetric, hece aligig o the rig cetre ca be cosidered the same as aligig o the core cetre. Corig ClearCurve ZBL (Trech type G657B3) spliced to itself Left fibre: Corig ClearCurve ZBL Right fibre: Corig Clear Curve ZBL

6 Corig ClearCurve ZBL (Trech type G657B3) spliced to SMF Left fibre: Corig ClearCurve ZBL Right fibre: G652 SMF Sitomo PureAccess-R5 (Trech type G657B3) spliced to itself Left fibre: PureAccess-R5 Right fibre: PureAccess-R5 Sitomo PureAccess-R5 (Trech type G657B3) spliced to SMF

7 Left fibre: Right fibre: PureAccess-R5 G652 SMF Does the splicer eed special software to splice G657 fibres? Fixed v-groove splicers: T-25e, T-66 o No special software is eeded. These splicers caot see the core so they do t care if the core looks differet to a G652 fibre core. Just use the SMF Stadard program ad make a Arc Test before startig to splice. Core aligig splicers: T-39 o Software before 1.26 ad 1.46 These software versios caot make Core aligig splices o BedBright XS or Corig ClearCurve. As a stop-gap, you ca create a SMF program that uses Diameter aligmet. Splicig BedBright XS to BedBright XS usig Diameter aligmet o a T-39 gives a typical break ad remake isertio loss of about 0.04 to 0.05dB. This is oly about a 0.02dB icrease over the value achieved usig later software versios which ca splice with Core aligmet. Due to EZ-Bed s simple image structure it s quite likely you ca splice it usig the SMF Stadard program. Although this should make good splices, the loss estimate may be too low, as the SMF Stadard program asses a 9 MFD. o Software versios 1.26 ad 1.46 This ca make core aligmet splices of BedBright XS produced up to mid-2009, but ot o more

8 recetly produced BedBright XS. It has special programs for splicig the pre-mid-2009 desig of BedBright XS to itself ad to G652 fibre. o Software versios 1.28 ad 1.48 This software has two major ehacemets over earlier versios A more resiliet image processig algorithm for Core aligmet A ew Adaptive aligmet mode, which ca be maually selected if the improved Core aligmet mode still fail to alig the fibres. This software has special programs for Core aligmet splicig of BedBright XS, EZ-Bed ad the void assisted versio of Corig ClearCurve, both themselves ad to G652 fibre. The BedBright XS program will also splice BedBright Elite. o Software versios 1.32, 1.52 ad 1.72 This software has 3 ew splice programs A program for core aligmet splicig of Sitomo PureAccess-R5 A program for core aligmet splicig of Prysmia CasaLight+ to itself A program for core aligmet splicig of Prysmia CasaLight+ to G652 fibre Although Corig's void assisted ClearCurve fibre has ow bee withdraw from the market, the T-39 retais the dedicated "BIF ClearCurve" program for splicig this fibre. If you're splicig Corig ClearCurve LBL or ClearCurve ZBL it's ot ecessary to use the "BIF ClearCurve" program. Just choose the "BIF Adaptive" program ad the T-39 should make a core aligig splice o these fibres. Support Cotact Details For product support cotact: support: seel@sielectric.com Address: Sitomo Electric Europe Ltd. Uit 220, Ceteial Park, Mai Tel: +44 (0) Mai Fax: +44 (0) Ceteial Aveue, Website: Elstree, Herts. WD3 3SL. UK 2011 Sitomo Electric Europe Limited