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  • Dubai 2008.May

    10 Gigabit EthernetTesting of installed fiber optic links A foundation for todays and future

    high performance applications

    10 Gigabit EthernetTesting of installed fiber optic links A foundation for todays and future

    high performance applications

    Mike KazemianSynergix

  • Dubai 2008.May

    SummaryLong awaited guidelines for fiber testing clarify details about how to certify fiber links to be ready for 10G. This presentation covers what we can expect from ISO/IEC 14763-3 and how the use of simple light sources and power meters can be complemented by the use of an OTDR, ensuring optimized margins and consistent installation quality.

  • Dubai 2008.May

    Agenda Standards Update: What is new in ISO/IEC

    14763-3 Short Review of legacy methods What is new and which questions are

    answered Which questions are new or remain

    unanswered Significance of Launch Conditions A clarification of the referencing method

    ending an ongoing confusion Advantages of an extended test regime

    Example for a combined field measurement with LSPM and OTDR

    Significance of accuracy in Data Center applications

  • Dubai 2008.May

    10 Gb Ethernet

    Approved by TIA in June 2002 A trend finds its continuation

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    Smaller loss budgetsSmaller loss budgets

  • Dubai 2008.May

    Relevant International Standards

    ISO/IEC 11801:2002 (EN 50173-1:2002): Define Links and Channels limits Relevant parameters are Length and Insertion Loss

    ISO/IEC 14763-3 (EN 50346): defines details about the test set up (Has been recently

    reworked)

    IEC 61280-4-1: (2003) Defines more details about Referencing Methods for Link &

    Channel and launch condition of the light source. (CPR = Coupling Power Ratios)

  • Dubai 2008.May

    The choice of light source is essential

    1st 850nm

    Std Dev2nd 850nm

    Std Dev

    VCSELLED w/mandral

    LED0.00

    0.20

    0.40

    0.60

    0.80

    1.00

    1.20

    dB

    50 m 50/125 um 850 nm Test Comparison

    VCSELLED w/mandralLED

    VCSEL 0.40 0.08 0.65 0.10LED w/mandral 1.08 0.01 0.97 0.04LED 1.10 0.05 1.02 0.08

    1st 850 nm Std Dev 2nd 850 nm Std Dev

    OTDRs always use a laser Legacy Standards define

    CPR= Category 1 (Overfilled Launch = LED)

    Future standards will be even more specific

  • Dubai 2008.May

    Why the overfilled LED always had been the right light for testing links.

    ISO/IEC 11801: 2002Technical Report ISO/IEC TR 14763-3

    MM: Method 2 of IEC 61280-4-1SM: Method A1 of IEC 61280-4-2

    >> The modal launch conditions from the light source shall be characterized as one of categories 1 through 5 following the procedure in annex A. If not otherwise specified in a reference document, light sources from category 1 shall be used and noted in the test report (see 7.1). Category 1 sources result in the highest measured cable plant loss.

  • Dubai 2008.May

    Review of common test methods

    5 foils show historically used methods Some common methods were not correct Methods were based on partially invalid

    assumptions

  • Dubai 2008.May

    Method B one jumper reference

    Setting referenceSetting reference

    dBdB

    AddedAdded

    dBdB

    includes link includes link + + ALLALL connectorsconnectors

    Supports a Permanent Link Measurement

  • Dubai 2008.May

    Method A Two Jumper Reference

    Unfortunately is the most often intuitively used method is not correct

    dBdB

    Setting ReferenceSetting Reference

    includes Link includes Link + + only oneonly one EndEnd--

    ConnectorConnector

    dBdB

  • Dubai 2008.May

    Method 3 Three Jumper Reference

    ReferencingReferencing

    Includes Link/Channel Includes Link/Channel BUT NOBUT NO

    End ConnectorsEnd Connectors

    dBdB

    The connector can be The connector can be a different type then a different type then the one on the OLTSthe one on the OLTS

    dBdB

    Supports a Channel

    Measurement

  • Dubai 2008.May

    3.2 dB noted for Gigabit in 568-BTest Example

    Source Meter

    850 nm1300 nm

    62.5/125 m cabling100m backbone cable6m patch cord106m to the wall outlet

    Method A =3 Connections @ 0.7 dB plus0.6 dB for fiber = 2.8 dB

    Method B =4 Connections @ 0.7 dB plus0.6 dB for fiber = 3.4 dB

    Method C =2 Connections @ 0.7 dB plus0.6 dB for fiber = 2.0 dB

    Method AA =3 Connections @ 0.7 dB plus0.6 dB for fiber = 2.8 dB

    Method BB =4 Connections @ 0.7 dB plus0.6 dB for fiber = 3.4 dB

    Method CC =2 Connections @ 0.7 dB plus0.6 dB for fiber = 2.0 dB

    Method BB results in a correct FAILHorizontal Cables

    Backbone Cables

    TR

    TR

    MCX

    XX X

  • Dubai 2008.May

    Inconsistent nomenclature caused additional confusion

    Similar methods used very different and often misleading names

    Standard Mode NameEIA/TIA-526-14A-98 Multi

    SingleMulti

    Single

    Method A Method B Method CEIA/TIA-526-7-98 Method B.1 Method A.1 Method C.1IEC 61280-4-1 Method 1

    2 jumper reference

    Method 21 jumper reference

    Method 33 jumper reference

    IEC 61280-4-2 Method 1bTwo jumper cable measurement

    Method 1aOne jumper cable measurement

    Method 1cThree jumper cable measurement

    ChannelPermanent Link

  • Dubai 2008.May

    Lets refresh what is Method 3 - Three Jumper Reference

    includesLinkincludesLink/Channel /Channel BUT NOBUT NO

    End ConnectorsEnd Connectors

    dBdBdBdB

    Supports a Channel

    Measurement

  • Dubai 2008.May

    The test leads decide about the relevance of test results

    Source

    Analysis of two extreme cases using the 3 Cord Referenz MethodeCase 1:

    The test leads show a typical value for the Mated ILx2y1 = x2d1 AND y2z1 = d2z1. The measured IL is that of the cable without connecting hardwareNOTE: There is no foundation for assuming a typical value

    Case 2:The test leads showing an ideal IL close to 0dB x2y1 = 0dB und y2z1 = 0dB. The measured IL is that of the link including* the connecting hardware

    NOTE: *) measured mated IL that of a perfect cord mated with a random cord

    Meter

    Source Meter

    x y zx2y1 y2z1

    Referencing

    dx zx2d1 d2z1

    Measurement

    Case 1

    Case 2

  • Dubai 2008.May

    Finding leading to parts of ISO/IEC 14763-3A. All Methods for referencing assume that the mated IL of test

    leads is the same as randomly mated connectors1) This can not be assumed2) The performance of test leads is significantly affecting the

    measured values3) 1 Jumper Method is least affected by this incorrect assumption.

    B. The distribution of power amongst modes has a significant affect on the measured IL

    1) The lack of HOMP (Higher order mode power) will lead to optimistic results

    2) Mandrels only represent a partial solution and need to be combined with a well defined launch condition

    3) VCSEL light sources suffer HOMP and a mandrel would if anything make it worse

  • Dubai 2008.May

    What is new and different in ISO/IEC 14763-3

    ISO/IEC TR 14763-3 (2000) NEW ISO/IEC 14763-3 (2006)Technical Recommendation International Standard

    12 pages 62 Pages

    Refers to 1 of 3 methods for referencing in IEC 61280-4-1 (MM) & 61280-4-2 (SM)

    Two Reference methods defined3 jumper reference (primary)1 jumper reference (secondary)

    Specifies Light source has to have a of Category 1 CPR (coupling power ratio)

    Defines MPD of light source (Modal Power Distribution)CPR as a secondary definition

    Inspection of fiber end faces

    Defines 2 test regimesBASIC: LSPM (Light source & Power Meter)EXTENDED: OTDR (Reflektometer)Method for (re) qualification of test leads

  • Dubai 2008.May

    The NEW The Three Jumper Reference Similar in process to the old method which assumed that the mated IL of a test

    lead is similar to when mated with the link The new method assumes test leads with connectors of reference quality

    Max. 0.1 dB Reference Plug Reference Plug Max. 0.3 (0.5) dB Reference Plug Random Plug (SM) Max. 0.75 dB Random Plug Random Plug

    T