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Installation and testing

September 2013

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Safety

Potential sources of risk:

• Active component (Laser)Injury of eyes and skin

• Fiber stub (cleaved fiber)Injury of eyes and skin

• ConsumablesChemicals and its vapor

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Cable deployment

Indoor OutdoorLatter buried aerial under waterDuct direct direct

Conduit Duct

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Installation methodology

Installation methodology depends on type of cable, distance, application and environment

pulling

layingwrapped

aerialblowing

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Connector cleaning

source:JDSU

Finger print Contamination Clean

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End face

Small parts on the fiber core cause significant return loss (RL) and insertion loss (IL)

Light (RL) (IL)

Contamination

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Cleaning – Ferrule/end face

Contaminated end face / fiber core

impress of dust parts when connecting

Permanent damage on fiber core

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Cleaning - Sleeve

Contaminated sleeve

Dust pushed during plug inof connector

Dust ring on ferrule andpotentially fiber core

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Testing

September 2011

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Inspection/verification test

Test

Equipment

Power Meter &

Light sourceOTDR

Fiber/Connector inspection

Visual fault locator

Total optical loss

Reflection Link characteristic

Visuelle inspection

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Visual inspection

Connector• Contamination• Damage

Identification• Fiber break• Bending• Faulty connection

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Measurement principales

OTDR

Rückstreumessung (OTDR)

Power meter

Power MeterLight source

Power MeterStecker

Light sourceStecker

OTDRSteckerStecker

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Power budget calculation OF-500

Connection Splice Connection Connection

200 m50 m250 m

PM

D

PM

D

Component ISO11801 “state of the art”Fiber OM3 3.5db/km 1.75dB 2.8dB/km) 1.40dB

Connector 0.75dB/Steck 2.25dB 0.5dB/Steck 1.50dB

Fusion splice 0.3dB/Spl 0.30dB 0.1dB/Spl 0.10dB

Dämpfung Gesamt 4.30dB 3.00dB

Channel attenuation for OF-500 at 850nm -> 3.25dB

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Power measurement – level setting

Transmitter

Test cable 1

1. Reference measuring

Adjust:Attenuation = 0 dB

Receiver

Test cable 2

850 nm0.00 dBm

nm850

0.00 dBmnm850

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Power measurement – link evaluation

Transmitter

2. Measuring the system’s attenuation

Receiver

LWL - Anlage

Total attenuation [dB]

850 nmÐ 0.74dBm

nm850

Ð 0.74dBmnm850

Test resultAttenuation = 2.1 dB

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Power measurement testing

Methodology according ISO/IEC 61280-4

Methodology 3 - KanalCC CC

Lichtquelle

S C

Launch cable

Powermeter

DC

Test JumperMethodology 2 - PL

Methodology 1 - CP

Depending on the reference measurement (1, 2 or 3 test jumper) a different result will be achieved.

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Error reduction: Mandrel wrap principle

50 m mandrel 18 mmfor 3 mm jumpers

62.5 m mandrel 20 mmfor 3 mm jumpers

9 m N.A.

Test jumper length 1 m to 5 mMandrel

Launch cord5 wraps

This “mode filter” causes high bend loss

in loosely coupled modes and low loss

in tightly coupled modes. Thus the

mandrel removes all loosely coupled

modes generated by an overfilled launch

in a short (cords) link used during the

reference setting

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Optical Time Domain Reflectometer OTDR

t

Measuringdelay

Receiver Evaluation

Impuls-generator

Lightsource

Beam splitter

optical Signalelectrical Signal

LWL

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OTDR measuring

OTDR

The reflected light pulse is detected by the OTDR.

The light pulse is partly reflected by an interfering effect.

OTDR

A light pulse propagates in an optical waveguide.

OTDR

Rayleigh scattering and Fresnel reflections

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An example of an OTDR waveform

Attenuation(dB)

Distance (km)

OTDR

Fusion- Connector Fiber Mech. Fiber-splice bend splice end

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OTDR pulse width

Larger pulse width:• More power, larger dynamic range

Shorter pulse width:• better resolution, dynamic range reduced due to more

incidents recognized.

OTDR PulseOTDR Pulse length in fiber

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DynamicRange Measurement Range

Noise floor

PMAX Backscatter level at OTDR test port

Dynamic range of an OTDR

dB

km

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Ideal trace of a reflected event with shortest pulse width, PMIN

PMIN

0.5 dB

1.5 dB

Attenuation- & event dead zone OTDR

Measured OTDR trace

Event dead zone

Attenuation dead zone

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Power measuring with OTDR

1) launching fiber 2) launching fiber200 m - 500 m for MM 200 m – 500 m for MM

500 m - 1’000 m for SM 500 m - 1’000 m for SM

FO system under test1) 2)

Test set up

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OTDRscreen

0

0 25050 100 150 200

-2

-1

-3

-4

Rel

ativ

e P

ower

(dB

)

Distance (m)

A B

Link beingtested

OTDR

LaunchCable

HorizontalSegment

BackboneSegment

ReceiveCable

SplicePatch Cord

LaunchCable

Splice(Loss 0.1 dB)

Rcv.Cable

TraceHoriz.Seg.

(2) Connections (Loss 0.8 dB)

BackboneSegment

(1) Connection(Loss 0.4 dB)

Link Loss ( 2.1 dB)

(1) Connection(Loss 0.4 dB)

Link Length ( 130 m)

Reading an OTDR Trace

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Other FO measurements

BandbreiteThe bandwidth is measured by the manufacturer of the fiber and guaranteed. Some cable manufacturer test this occasionally. There is no point to test in the field or it is very expensive.

Polarisationsmoden Dispersion (PMD)Only for Single mode applicationChannel length > 2 km