otdr 101 - getting confortable with exfo otdrs

1© 2010 EXFO Inc. All rights reserved.

OTDR

Product & Technology overview

Presenter:Jimmy GagnonProduct Specialist, EXFO [email protected] March 2011


1 Basic OTDR principles2 Multimode fiber introduction3 OTDR applications and portfolio4 OPEX-saving softwares & applications5 EXFO’s support6 How to analyse OTDR results

Today’s GOALS:


Basic

OTDR principles


OTDR Overview

Simplified Optical Time Domaine Reflectometer ( OTDR )

3 basic parameters that define how the OTDR responds to various lengths of optical fiber

Why use an OTDR?

In this section we will describe the following:


Simplified OTDR

The OTDR launches a pulse of LASER light into the optical fiber.

Reflections return to the OTDR from end-faces and other irregularities within the fiber.


Simplified OTDR

End-FaceConnector

OTDRs launch a series of pulses into optical fiber and plot the energy level and round-trip time of all reflections to create a trace.

The round-trip time is converted to distance on the trace.

ENERGY

DISTANCE


Simplified OTDR

Two types of reflection:

1- Rayleigh Backscattering Comes from the “Natural” reflection of the fiber The OTDR will use the Rayleigh Backreflections to measure fiber’s attenuation (dB/Km) Back reflection level around -75 dB Higher wavelength will be less attenuated by the Rayleigh Backscatter

Source

Ray of light

Silica particles


Simplified OTDR

Two types of reflection:

2- Fresnel back reflections

Will come from abrupt changes in the Refractive Indice ex: (glass/air)Fiber break, mechanical splice, connectors

Fresnel reflections will be approximately 20 000 times higher than fiber’s backscattering level

Will show as a “spike” on the OTDR trace


OTDR Trace Terminology

Splice tray

OLT

Inacti

ve

!

Splice tray C.O.

Backscatter line

Fresnel

Launch

Noise

Relative Power

End of Fiber Fresnel

Event


OTDR -- Basic parameters

OTDRs deal with multiple parameters that all interact with each other

OTDRs are a matter of trade-offs : gain this, loose that.

There are multiple recipies to get a good OTDR trace, as well as a bad one!


OTDR -- Basic parameter: Average Time

End-FaceConnector

By the time the primary pulse reaches the end of a relatively long optical fiber, most of its energy has been dissipated.

The OTDR records the results of the first pulse then launches another and then another. It ‘averages’ the results of multiple pulse launches to give the operator a clean trace

The more averaging time, the more dynamic range


OTDR -- Basic parameter: Distance Range

End-FaceConnector

This parameter does have an impact on OTDR functionality because, aside from scaling the graph, it is also used to determine how soon the OTDR launches subsequent pulses.

Essentially, it has some control over Pulse Repetition Rate.

A suitable distance will optimize the dynamic range


OTDR -- Basic parameter: Pulse Width

Pulse width is the parameter that has the greatest impact on OTDR performance. In fact, adjusting PW will impact both dynamic range and resolution in very predictable ways.

Put simply, the longer the LASER stays on the more energy is injected into the fiber and the greater the effective range.

Counter side is the resolution of the pulse is reduced and increases the dead zones



Short pulses will give a better resolution but less dynamic range:

Long pulses will give a better dynamic range but less resolution:

Two connectors 3 meters apart

End of link (patch panel)

Connectors are

measured for

distance and

marked as separate events

Connectors are

« merged » and

identified as one event

End of fiber is not reached due to low power of

short pulses

End of fiber is reached and located

5ns pulse

30ns pulse



Event dead zone

The event represents the minimum distance between the beginning of a reflective event and the point where a consecutive reflective event should clearly be recognized.

Dead zone concerns only reflective events

-2.00

-4.00

-6.00

-8.00

-10.00

100.00 110.00 120.00 130.00 140.00 150.00 160.00

dB

Metre

1.5 dB

Event Dead Zone

It is the distance between: The beginning of the events

the -1.5 dB point on the falling edge



Attenuation dead zone The minimum distance between two consecutive

reflective or non-reflective event in order for the OTDR to perform loss measurement.

It is the distance between:The beginning of the events the

point on the falling edge where the receiver sees a value around

0.5dB from the normal backscatter trace

-2.00

-4.00

-6.00

-8.00

-10.00

100.00 110.00 120.00 130.00 140.00 150.00 160.00

dB

Metre

Attenuation Dead Zone

0.5 dB


OTDR – A tool of choice, WHY?

It reveals what?

Total Loss

Optical return Loss

Fiber Length

It is use for what?

Characterize the link components

Highlight a potential problem

Locate a fault


What we’ve learned so far -

OTDRs launch a series of pulses and plot the energy level and round-trip time of all reflections to create a trace.

OTDRs deal with multiple parameters that interact with each other

The Distance Range setting tells the OTDR software how to scale the screen as well as how long to wait between pulses to allow all reflections sufficient time to return.

The Average Time setting tells the OTDR how long to average the reflections from multiple pulses to obtain a ‘clean’ trace.’

The pulse width setting tells the OTDR how long to leave the LASER on for each pulse.

- Long pulse widths have greater range. - Short pulse widths have greater resolving power (to show closely spaced

events).


• Categories• Light sources• Problems

OTDR

Multimode fibers


Multimode Fiber -- Categories

› There are two types of fiber:› Singlemode fiber (SMF)› Multimode fiber (MMF)

› MMFs are categorized as follows:› 62.5 µm/125 µm (called OM1)› 50 µm/125 µm (called OM2, OM3 or

OM4 depending on fiber characteristics)

› OM4 was standardized in 2009Image: courtesy of Corning cable


Multimode Fibers -- Light Sources

› Different MMFs meet different demands for bandwidth, distance and cost

› With bandwidths beyond 100 Mbit/s (1 Gbit/s - 10 Gbit/s), Tx changed from a LED to laser (VCSCEL)

› LEDs and lasers have different spectral characteristics; hence, the need for OM3 and OM4 laser- optimized MMF

Image; courtesy of Corning Cable

LED

Laser


› MM IL measurement is highly sensitive to source launching conditions

› For example, the IL of a connector varies greatly according to the launching conditions of the light source, typically used in the industry to perform the measurement

Multimode Fibers -- The Real Problem

Source Launching Conditions

Measured Connector IL

Overfilled (e.g., surface emitted LED)

Slightly under filled (targeted EF conditions)

Loss over estimated (IL = 1 dB to1.5 dB)

On target (IL = 0.5 dB)

Under filled (e.g., VCSEL or

edge emitting LED)

Loss under estimated (IL = 0.02 dB)


• PON FTTH / MDU• Metro / CWDM / Long-Haul• Data centers

OTDR

Applications


Applications -- FTTH / MDU

More information available on EXFO’s Expertise Hub


Applications -- FTTH / MDU

26© 2010 EXFO Inc. All rights reserved. 26© 2010 EXFO Inc. All rights reserved.

Applications – Metro/Core

Metro – long range

Core – Medium range


CWDM – Business services


Applications – Cell backhaul


Applications – Data centers

- Short distance- Multiple connections- High reflections- Must meet TIA/EIA standards- Requires launch and receive

cables for end-to-end loss


Applications – A solution for each topology

Fibre Copper / Coax

CoreLong HaulNetwork

Local Access Network

Premises NetworkEdge

CATV

cell site

Metropolitan Network

FTB-200 or 500 7400E Series

FTB-200 or 500

With 7500E or 7600E Series

AXS-100 SM for troubleshooting.

FTB-1 with 720

AXS-110 SM for troubleshooting.

FTB-200 with 7200D or 7300E Series

AXS-110 Quad.

FTB-1 with 720 SM/MM

AXS-110 PON.FTB-1 with730 PON

FTTx


EXFO

OTDR Solutions


EXFO SOLUTIONS -- Built to make a difference


EXFO SOLUTIONS -- Built to make a difference

No1 OTDR manufacturer in the world


EXFO SOLUTIONS -- Built on real-world EXpertise

› 20 YEARS OF OTDR DEVELOPMENT

› ACCELERATE WORKFLOW IN THE FIELD.

› TIME-SAVING FEATURES

› BENCHMARK SPECIFICATIONS, POWERFUL ALGORITHMS, BEST TRACE ANALYSIS

Make your first acquisition the right one


FTB-1 – 1-slot modular platform

EMPOWERINGFRONTLINE TECHNICIANS

› 7-INCH TOUCHSCREEN DISPLAY

› UNIQUE HYBRID-TOUCH CONTROL

› SMALLEST AND LIGHTEST FTTX/10G PLATFORM (33% THINNER)

› UNMATCHED BATTERY LONGEVITY› OTDR: 8 hours› 10 Gbit/s Ethernet: 4 hours

2x

http://www.google.ca/imgres?imgurl=http://netbook-planet.com/wp-content/uploads/2010/05/Intel-Atom-logo.jpg&imgrefurl=http://netbook-planet.com/2010/06/27/intel-atom-dual-core-processors-explored-d510-and-d525/&usg=__uVP7yI71eUTlNw_3_Gxhjk6MooU=&h=372&w=300&sz=41&hl=en&start=2&zoom=1&um=1&itbs=1&tbnid=euJj3p09RwLCAM:&tbnh=122&tbnw=98&prev=/images?q=intel+atom&um=1&hl=en&rlz=1T4SUNC_enCA386CA386&tbs=isch:1


Internet Explorer Bluetooth Data Mover

› INTEGRATED UTILITIES FOR WORKFLOW EFFICIENCY

› LEVERAGING CONNECTIVITY TO INCREASE AUTONOMY

› EFFORTLESSLY RECEIVE AND TRANSFER FILES/DATA

› Quick data file transfer to smartphones and PCs for upload to central office

› Simple, quick and intuitive software upgrade wizard

› View/connect to Wi-Fi networks and save profiles for quick configurations

› Browse the web, access online info and web e-mail accounts

Update Manager Wi-Fi Wizard

FTB-1 – 1-slot modular platform

EMPOWERINGFRONTLINE TECHNICIANS


FTB-200 – 2-slot Compact platform

THE INTELLIGENT PLATFORMBUILT FOR THE SUPERTECH.

› 6.5-INCH TOUCHSCREEN DISPLAY

› HOSTS TWO MODULES FOR MULTI-TASKING

› COMBINES OPTICAL AND DATACOM TESTING


FTB-500 – The multi-module platform

BOUNDLESS CAPABILITIES.TESTING UNLIMITED.

› 12-INCH TOUCHSCREEN DISPLAY

› FASTEST TESTING, UNMATCHED CRUNCHING POWER

› REMOTE CONTROL CAPABILITIES

› EVOLUTIVE AND FUTURE-PROOF


• Inspection Probe• Connector Max• Chromatic Dispersion• PMD• OTDR• OLTS

Our Solution – MODULAR FTB-500

FTB-500 : All-in-one physical layer characterization


AXS-100/110 SERIES – POWERFUL HANDHELDS

THE LIGHTWEIGHT AND COMPLETE HANDHELD

› FAST-TRACE AUTO-TESTING

› FROM LAN/WAN TO PON LIVE TESING

› BATTERY LIFE OVER 8 HOURS

› INDUSTRY-LEADING SPECIFICATIONS

APPLICATIONS

• FTTx/MDU networks -- PON-optimized and in-service testing

• LAN/WAN -- MM/SM combined

• Private networks -- Integrated power meter, VFL, inspection probe

• CATV – point-to-point tesing and high-power GeX detector


CHOOSE THE BEST FIT

THE PLATFORM IS THE DIFFERENTITOR

Manager 1Has single-task technicians doing mainly OTDR testing

Single-module for dedicated application

FTB-1/FTB-700

FTB-200FTB-7000

Manager 2Requires multi-applications support such as : OTDR+Ethernet, OTDR+OLTS, OSA, CD/PMD

2-slot modular for combined applications


Our Solution – A great portfolio for today’s needs

AXS-100

Our last mile & troubleshooting

solution

FTB-200 with

FTB-7000

Our 2-slot modular combined solution

AXS-110

Our Handheld «PON »

& SM/MM tool

FTB-500 with FTB-7000

Our fiber characterisation

kit

FTB-1

Our 1-slot modular dedicated solution


Our Solution – Accessory – Launch Test Cable

By the way… A Launch Test Cable is the perfect add-on to an OTDR test kit. The FTB-LTC module fits nicely beside the OTDR module in both the FTB-200 and the FTB-500 platforms

› Used to eliminate OTDR’s first & last connectors dead zones,

for end-to-end characterization

› Saves the OTDR’s connector life by reducing matings (high-count fiber cable testing)


OPEX-saving softwares & applications

• Fast Report & Lite Reporter• Connector Max


POST-PROCESSING & REPORTING Fast & Lite Reporter


Often get a lot of files to analyze Have to manually add and remove events on OTDR files Need to integrate different measurements in one report (OTDR, Loss, ORL, CD and PMD) Customizing reports is not an easy task Post processing is long, boring and complicated!

Customer day-to-day reality


Windows based software, easy to use and with an intuitive GUI OTDR cable « Live Templating » Powerful batch processing Faster than ever batch bi-directionnal analysis Flexible reporting A good way to futurproof your network

Our solution


CONNECTOR MAX INCREASED PRODUCTIVITY

FIP-400 CONNECTORMAX:ELIMINATE GUESSWORK AND ACHIEVE

CLEAR-CUT ENDFACE ANALYSIS

› Automated pass/fail analysis

› Results/auto-save/auto-report in 4 seconds with one-touch operation

› Full test reports for future referencing

› Works with your FTB-500, FTB-200V2, FTB-1

› Completes your FIP-400 inspection probes



ELIMINATE GUESS WORK1



ELIMINATE GUESS WORK2


EXFO’s SUPPORT


Our EXpertise– Did you know?

1 2 3

http://www.exfo.com/en/Products/OTDR

Introduction Overview Virtual Demo

OTDR Brochure


Our Expertise – Ressources – How we can help?

Be-an-Expert Technical Training ProgramMultiple training and learning toolsOnline capsules and on-site trainingsPlanned webex trainings

MY EXFO (FREE registration)Download softwares, product literaturesAccess online trainingsCreate and monitor product-support tickets


Getting down to work

How to analyse OTDR results


Macro-Bend dropped 1550nm

The customer first thought

the OTDR had malfunctioned

.

1625 nm

1310 nm

1550 nm

8.7 kft

19.9 kft

1310 nm: normal OTDR trace1550 nm: huge event loss1625 nm: end-of-link located at 8.7 kft

macrobends


What’s Wrong With This One?


High Reflectance At Launch

Suggested Action:

• Clean Connectors

• Replace Test Jumper.

• Use FTB-LTC

First Event


End of Fiber Not in Range

This may lead to anomalous “events”

For example, end-of-fiber fresnels may be registered

as events/splices


Echos

Event#4 is not “real”

It shows no loss and corresponds to the double distance of another event

Identified with an icon

Suggested Actions: High reflections, particularly in MM testing, generate echos. Try to minimize reflectances for better measurements


Frontend “dead-zone”

10 nS Pulsewidth – 8 meter dead-zone on front end.

This includes effects of pulsewidth and photodiode

saturation.

Suggested Actions – add FTB-LTC or launch test cables and retake trace – this moves events out of front-end dead-zone. Backscatter dead-zone is approximately 1.5 meters at this pulsewidth so closely spaced events can be more easily differentiated/measured if they are out of the launch dead-zone.


Fusion Splice

This splice has excellent “low loss”

characteristics but may be difficult to measure

and/or locate

Suggested Actions: acquire a ‘reference trace’ and manually mark any splices that the OTDR was unable to locate. Then store this trace for comparison to future traces. Acquiring and storing well-documented reference traces may be vital to future operations or trouble-shooting.


Out of Range

This trace was taken using a 275 nS

Pulsewidth.

Suggested Actions: Increase Pulsewidth and retake trace. Increase average time for marginal gains in trace readability.


Thank [email protected]

otdr 101 - getting confortable with exfo otdrs

Documents

ftth mdu

inch touchscreen display

reporting fast

slot modular platform

eliminate guess work

simplified otdrtwo types

analyse otdr results

multimode fibers