Nd At S Best Practices For Single Mode Tier I Ii Testing 01 2011

Best Practices Tier I and Tier II Testing Telecommunication AT&S Conference

Outline Field Testing: Cleaning & Visual Inspection Optical Loss Testing OPM & OLS Setting Reference Optical Time Domain Reflectometer Testing Analyzing traces Identifying Anomalies

Basic Field Tests Visual Inspection Continuity

Basic Field Tests Source/Meter Attenuation Test (Tier 1) OTDR (Tier 2)

Cleaning tools of the trade VFI 2 Cletop & Cleaner VS300 OTDR w Probe One-Click OFI200

FCC2-Fiber Connector Cleaner Nonflammable/Air cargo safe Environmentally safe Fast drying without residue Dissolves light oils, salts, grime and uncured epoxies Up to 400+ cleanings per container

CCT- Connector Cleaning Tips Used with FCC2 Molded polymer construction No fibers, binders, adhesives or outgassing to contaminate connectors Traps and holds liquid and particles contaminates Perfect bulkhead fit

Basic Light Test Continuity Visual Fault Identifier AKA “VFI” Low cost polarity/continuity checker Key tool in near end fault location Works where OTDR and OLS/OPM may not Insert connector into a Visual Fault Identifier (VFI) Place a small bend in the 900 micron fiber behind the connector A “red light” at the bend will indicate that the connector is passing light

Basic Light Test Continuity Visual Fault Identifier AKA “VFI”

The Connector End-Face Inspection Clean/defect free connections typically yield lower loss and prevent possible future link failures Verify no energy with OPM or OFI Inspect connector end-face for dirt Clean Connector with CLE-TOP or One-Click AT&T standards outline 3 dry cleans and 2 wet cleans Once cleanliness at all adapter points is verified use meters/OTDR to determine link is good

The Connector End-Face Body oil (don’t touch the connector end-face!) Multimode Connector

Attenuation Test Set SLP 5-6 Test Kit Most accurate measurement of total link attenuation Automatic continuity check Does not identify or evaluate specific events in the link Wave ID speeds testing at multiple wavelengths

OLS 2-DUAL Laser Source 1310/1550 nm Wave ID Transmit 2 KHz for fiber ID Small size

OPM 5 Optical Power Meters +6 TO -70 & +26 to –50 dBm range 850/980/1310/1490/1550 & 1625 nm Set Reference Feature Wave ID Detect Tone Detect Data Storage-multiple files PC Software (TRM)

Testing fibers To test fibers using an OPM & OLS you should have: Two good reference jumpers with connectors that match the fiber under test (the reference fiber type, or core diameter, should match the fiber under test) Coupling to test the receive jumper after setting the reference Cleaning supplies

ONE-JUMPER REFERENCE Light Source Optical Power Meter Set reference w 1 Jumper (Tx) Tx jumper Tx Rx ANSI/TIA/EIA-526-14 Method B Connect Tx jumper between OLS & OPM Press Set Ref button until HELD displayed. Display should show  0.00 dB at the test wavelength(s)

Verify (Rx) jumper Do not disturb Tx jumper at OLS Rx jumper 3. Verify Rx jumper TIA allows 0.75 dB 0.3-0.5 dB typical Adapter Light Source Optical Power Meter Tx jumper ANSI/TIA/EIA-526-14 Method B Change OPM adapter cap (if necessary) 4. Separate the jumpers at the adapter and begin testing ONE-JUMPER REFERENCE

Optical Time Domain Reflectometer (OTDR) OFL280 OTDR Hand Held tool with simple user interface: Generates a baseline trace A “visual” of the link Fiber acceptance tool Excellent documentation Can identify and evaluate specific events in the link Fault location tool Limited use in short length fibers

OTDR Block Diagram Control Unit Laser Transmitter Detector LCD Display Splitter Fiber Under Test

Fiber Rings & Using an OTDR Use a launch cable to measure the loss of the near-end connection Use a receive cable to measure the loss of the far-end connection Fiber Rings must use the same type fiber (50  m, 62.5  m, or single mode) as the link under test For testing links under 2 km, the length of the launch and receive cables should be about 100 m (use our 150m)

Generating an OTDR Baseline Trace Intermediate Cross Connect Splice Main Cross-Connect A A B B B A A B Fiber Ring Pulse Suppressor Horizontal Cross-Connect Pulse Suppressor

Backscatter Backscatter portions of an OTDR trace show power (in the fiber) vs. distance Power (dB) Distance Backscatter

OTDR Settings Full Auto OTDR “pings” fiber to determine Range, selects an appropriate length greater than the fiber under test and uses the Pulse Width (PW) associated with that range. Full Auto Pings every fiber Simplifies testing for new technicians Assures range setting appropriate for fiber length Expert Auto-Once Pings the first fiber then uses the same settings for all subsequent tests. A user can adjust the settings from the Auto-Once determined settings Reduces Test Time Risk of not resetting range for next tests when move from short to long fibers

OTDR Settings Expert (Manual) The User sets up the: Range Pulse Width Averages (Time) Reduces Test Time Risk of not resetting range for next tests when move from short to long fibers Examples follow

Range Too short : less than link length Link Can’t see entire link – unpredictable results Good : about 1.5x to 2x link length Link Good trace – can see end of fiber Too long : much larger than link length Link Trace is “squashed” into left side of display

Pulse Width Too wide: Can’t resolve events About right: Events can be seen and trace is smooth Too narrow: Trace “disappears” into noise floor Link Link Link Where is this event?

Pulse Width (PW) Long PW used for long Fiber Under Test or trace will be “noisy” or rough Short PW used for short Fiber Under Test, if use long PW on short fibers you may miss or clip events

Averages (Time) Too many Trace is smooth but may waste time with little improvement About right: Trace is smooth Too few: Trace is noisy – noise floor is too high Link Link Link

OTDR Settings: Group Index of Refraction If known a user should set the GIR to match the fiber they are testing Using a GIR that is different than the actual GIR of the fiber under test may over or under estimate the length of the fiber OTDRs typically have a default GIR value OFL280 Default Values: SM 1310/1550nm =1.4677/1.4682

OTDR Trace Mechanical Connection Dead Zone 0 200 400 600 800 End Spike Distance Attenuation (dB) Fusion Splice Ghost Reflection

The OTDR Trace Distance Units Attenuation A B DZ Connectors Big “Spike” High Fresnel Reflection

The OTDR Trace Distance Units Attenuation A B Fusion Splice or Macrobend No “Spike” Attenuation

The OTDR Trace Distance Units Attenuation A B Smaller “Spike” Less Fresnel Reflection Mechanical Splice or Angled Connector

The OTDR Trace: Anomalies Distance Units Attenuation A B Ghost 2X Distance from first event Not a real event No loss

The OTDR Trace: Anomalies Distance Units Attenuation A B Gainer An apparent increase in power Located at a fusion splice Significant loss if measured in the opposite direction

Conclusion clean, Clean, CLEAN! Optical Loss Testing Most accurate measurement of total link attenuation Automatic continuity check Does not identify or evaluate specific events in the link Wave ID speeds testing at multiple wavelengths Single jumper reference Optical Time Domain Reflectometer Testing A “visual” of the link Fiber acceptance tool Excellent documentation Fault location tool Limited use in short length fibers

Website: www.AFLglobal.com Click on: AFL Telecommunications / Products >> Noyes Test and Inspection Address: AFL 16 Eastgate Park Road Belmont, NH 03220 Telephone: 800-321-5298 (USA) 603-528-7780 ask for Technical Support or Sales Fax: 603-528-2025 To contact Noyes Fiber Systems

Nd At S Best Practices For Single Mode Tier I Ii Testing 01 2011

More Related Content

What's hot (18)

Viewers also liked (16)

Similar to Nd At S Best Practices For Single Mode Tier I Ii Testing 01 2011 (20)

Nd At S Best Practices For Single Mode Tier I Ii Testing 01 2011