Inspection and Cleaning
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Transcript Inspection and Cleaning
See the Light!
Part 1: Inspection and Cleaning
Agenda
Fiber Optics Key Concepts
– Fiber types and Connectors
– Fiber Connections: the good, the bad, and the ugly
– Measurement Units
Inspection and Cleaning
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Inspect Before You ConnectSM
Inspect Both Sides
Proactive Inspection
Cleaning Best Practices
Introduction to Fiber Testing
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Optical Communications
Communication technology, developed in the 70s, that
sends optical signals down hair-thin strands of glass fiber
Light Rays
Transmitter
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Fiber
Receiver
Optical Fiber Types
2 Types
Multimode
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Single-mode
Fiber Types MM
Fiber carries numerous light rays (mode)
simultaneously through the fiber.
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High attenuation
850 to 1300 nm transmission wavelengths
Local networks (<2 km)
Limited bandwidth
LAN/Industry
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Fiber Types SM
Fiber carries a single light ray (mode).
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Low attenuation
1260 to 1660 nm transmission wavelengths
Access/medium/long haul networks (>200 km)
Nearly infinite bandwidth
Telecom/CATV
FTTx
CWDM/DWDM
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Fiber Connectors are Everywhere!
Fiber optic connectors are common throughout the network as they
provide the power to add, drop, move, and change the network.
Local Convergence
Point
Buildings
Network Access
Points
CO/Headend/
MTSO
Feeder Cables
Distribution Cables
Drop Cables
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Residential
Multi-home
Units
Fiber Optic Connector
Body
Houses the ferrule that
secures the fiber in place
Ferrule
Thin cylinder
where the fiber
is mounted and
acts as the fiber
alignment
mechanism
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LC CONNECTOR
Ferrule
Cladding
Body
Core
Fiber: Cladding
Fiber: Core
Glass layer surrounding the
core, which prevents the signal
in the core from escaping
The critical center layer of the fiber;
the conduit that light passes through
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Anatomy of Fiber Connectors
Light is transmitted and retained in the CORE of the optical fiber by total internal
reflection.
The fiber connector
end face has 3 major
areas – the core, the
cladding and the
ferrule.
Particles closer to the
core will have more
impact than those
farther out.
Fiber End Face View
FERRULE – 1.25 or 2.5 mm
CLADDING – 125 µm
CORE – 9 µm (SM)
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Single Fiber vs. Multi-Fiber Connectors
SINGLE FIBER CONNECTOR
White ceramic ferrule
One fiber per connector
Common types include SC,
LC, FC, and ST
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MULTI-FIBER CONNECTOR
Polymer ferrule
Multiple fibers in linear array
(for example, 8, 12, 24, 48, and 72) in single
connector providing high-density connectivity
Common type is MPO or MTP®
Common Single Fiber Connectors
FC connector
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ST Connector
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2.5 mm ferrule
Push-pull latching mechanism
Most widely used connector today
(LAN/WAN)
LC Connector
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2.5 mm ferrule
Twist-lock mechanism
Legacy – mainly used with
multimode fibers
SC Connector
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2.5 mm ferrule
Screw mechanism with key –aligned
Legacy – mainly used with singlemode fibers
1.25 mm ferrule
Finger latch
Fastest growing connector
Types of End Faces
PC – Physical Contact
APC – Angled Physical Contact
The angle reduces the backreflection of the connection.
SC - PC
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SC - APC
Focus on the Connection
Bulkhead Adapter
Ferrule
Fiber
Fiber Connector
Physical
Contact
Alignment
Sleeve
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Alignment
Sleeve
What Makes a GOOD Fiber Connection?
The 3 basic principles that are critical to achieving an efficient fiber
optic connection are “The 3 Ps”:
Light Transmitted
Perfect Core Alignment
Physical Contact
Core
Pristine Connector
Cladding
Interface
CLEAN
Today’s connector design and production techniques have eliminated
most of the challenges to achieving core alignment and physical contact.
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What Makes a BAD Fiber Connection?
Today’s connector design and production techniques have eliminated most
of the challenges to achieving core alignment and physical contact.
The remaining challenge is maintaining a pristine end face. As a result,
CONTAMINATION is the No. 1 reason for troubleshooting in optical
networks.
A single particle mated
into the core of a fiber
can cause significant
back reflection,
insertion loss, and even
equipment damage.
Light
Back Reflection
Core
Cladding
DIRT
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Insertion Loss
Measurement Units
dBm unit is decibels relative to 1 mW of power
dBm is an ABSOLUTE measurement
dB is a RELATIVE measurement
Relative Power (dB) =10*Log
Pi(mW )
Pt (mW )
Pi(mW )
Absolute Power (dBm) =10*Log
1mW
Tx
1 mW = 0 dBm
2 dB
Loss = 8 dB
1 dB
5 dB
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0 dBm
-3 dBm
-20 dBm
-40 dBm
1 mW
0.5 mW
0.01 mW
0.0001 mW
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Rx
-8 dBm
Optical Loss Budget
Light Rays
Transmitter
Fiber
Receiver
What is the output power of the transmitter?
What is the sensitivity of the receiver?
The difference is the maximum amount of LOSS
allowable for the optical transmission line.
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Contamination and Signal Performance
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CLEAN CONNECTION
FIBER CONTAMINATION AND ITS EFFECT ON SIGNAL PERFORMANCE
Back Reflection = -67.5 dB
Total Loss = 0.250 dB
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DIRTY CONNECTION
CLEAN Connection vs. DIRTY Connection
This OTDR trace illustrates a significant decrease in signal
performance when dirty connectors are mated.
Back Reflection = -32.5 dB
Total Loss = 3.2 dB
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Illustration of Particle Migration
15.1µ
10.3µ
11.8µ
Core
Cladding
Actual fiber end face images of particle migration
Each time connectors are mated, particles around the core become displaced, causing
them to migrate and spread across the fiber surface.
Particles larger than 5 µm usually explode and multiply upon mating.
Large particles can create barriers (air gaps) that prevent physical contact.
Particles smaller than 5 µm tend to embed into the fiber surface creating pits and chips.
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Particle Migration and Signal Performance
Signal Performance
-70
-60
-50
-40
-30
-20
Actual fiber end face images of particle migration
Baseline/
Initial
Contamination
1st Mating
2nd Mating
For each successive mating, actual dB values increase as signal performance
decreases
Dirt particles near or on the fiber core significantly affect signal performance
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3rd Mating
Dirt Damages Fiber!
Mating dirty connectors
embeds the debris into
the fiber.
Light
Back Reflection
Insertion Loss
Core
Cladding
Mating force of 2.2 lb
over 200 um diameter
gives 45,000 psi.
PITS
DIRT
(permanent damage)
Once embedded debris is removed, pits and chips remain in the fiber.
These pits can also prevent transmission of light, causing back reflection,
insertion loss and damage to other network components.
Most connectors are not inspected until the problem is detected…
AFTER permanent damage has already occurred.
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Types of Contamination
Fiber end faces should be free of any contamination or defects, as shown below:
Single-mode Fiber
Common types of contamination and defects include the following:
Dirt
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Oil
Pits & Chips
Scratches
Contamination Categories
LOOSE
Most contamination comes from dry particles that have fallen onto
the end face or have been “placed” there during handling
BONDED
Most stubborn particles are held in place with grease, oils, or
dried residue from a wet cleaning process
MATED
Particles on the end face of a connector can also become
embedded into the glass if mated with another connector
CONTAMINATION MUST BE CLEANED from the end face prior to mating in
order to optimize the efficiency of an optical signal or interconnect
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Inspection and Cleaning
Inspect Before You Connectsm
Follow the simple “INSPECT BEFORE YOU CONNECT” process to ensure
fiber end faces are clean prior to mating connectors.
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Inspect, Clean, Inspect, and Go!
Fiber inspection and cleaning are SIMPLE steps with immense benefits.
1
Inspect
■ Use a probe
microscope to
INSPECT the fiber.
– If the fiber is dirty,
go to Step 2, Clean.
– If the fiber is clean,
go to Step 4,
Connect.
2
Clean
■ If the fiber is dirty,
use a simple
cleaning tool to
CLEAN the fiber
surface.
3
Re-inspect
■ Use a probe
microscope to
RE-INSPECT
(confirm fiber is
clean).
– If the fiber is still
dirty, repeat Step 2,
Clean.
– If the fiber is clean,
go to Step 4,
Connect.
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4
Connect
■ If the fiber is clean,
CONNECT the
connector.
NOTE: Be sure to
inspect both sides
(patch cord “male” and
bulkhead “female”) of
the fiber interconnect.
Inspect and Clean Both Connectors in Pairs!
Inspecting BOTH sides of the connection is the ONLY WAY to ensure
the connector will be free of contamination and defects.
Patch Cord (Male) Inspection
Bulkhead (Female) Inspection
Patch cords are easy to access and view compared to the fiber inside the bulkhead
(or test equipment or network equipment) which are frequently overlooked. The
bulkhead side may only be half of the connection, but it is far more likely to be dirty
and problematic.
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Proactive vs. Reactive Inspection
PROACTIVE INSPECTION:
REACTIVE INSPECTION:
Visually inspect fiber connectors
at every stage of handling
BEFORE mating them.
Visually inspect fiber connectors
AFTER discovering a problem,
typically during troubleshooting.
Connectors are much easier to
clean prior to mating, before
embedding debris into the fiber.
By this time, connectors and other
equipment may have suffered
permanent damage.
Dirty
FiberFiber
AFTER
PRIOR
Cleaning
to
Mating
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Dirty
FiberFiber
AFTER
PRIOR
Mating
to Mating
and
Numerous Cleanings
Benefits of Proactive Inspection
PROACTIVE INSPECTION is quick and
easy, with indisputable benefits
Reduce Network Downtime
Active network = satisfied customers
Reduce Troubleshooting
Prevent costly truck rolls and service calls
Optimize Signal Performance
Network components operate at highest
level of performance
Prevent Network Damage
Ensure longevity of costly network
equipment
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Cleaning Best Practices
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Many tools exist to clean fiber
Many companies have their own “best practices”
Dry clean first. If that does not clean, then try wet cleaning.
Always finish with dry cleaning!
© 2009 JDSU. All rights reserved.
Testing
Test!
Basic Tests
– Visual Fault Locator (VFL)
– Optical Insertion Loss
– Optical Power Levels
Advanced Tests
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Optical Return Loss (ORL)
Optical Time Domain Reflectometer (OTDR)
Chromatic Dispersion (CD)
Polarization Mode Dispersion (PMD)
Optical Spectral Analysis (OSA)
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Visual Fault Locator
VFLs provide a visible red light source useful
for identifying fiber locations, detecting faults
due to bending or poor connectorization, and
to confirming continuity.
VFL sources can be modulated in a number of
formats to help identify the correct VFL (where
a number of VFL tests may be performed).
FFL-050
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FFL-100
Insertion Loss
Single Direction Insertion Loss Measurement with a Source and Power Meter
Reference first!
Light
Source
Power
Meter
0dB
Reference Measurement
Light
Source
Power
Meter
-1.5dB
Insertion Loss Measurement
2255/45
1, 2, or 3 jumper references can be performed – 2 jumper shown
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2256/02
Advanced Tests
Optical Return Loss (ORL)
Optical Time Domain Reflectometer (OTDR)
– Detect, locate, and measure events at any location on the fiber link
Fiber Characterization
– Determines the services that the fiber can be carry
– Basic tests plus:
• Chromatic Dispersion (CD)
• Polarization Mode Dispersion (PMD)
Optical Spectrum Analysis (OSA)
– Spectral analysis for Wavelength Division Multiplexing (WDM)
systems
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Wrap Up
Summary
Always “INSPECT BEFORE YOU CONNECT”
Correct testing of the fiber optic link is critical
– Tests range from basic VFL/OIL to advanced
OTDR/PMD/CD
– Tests to perform depend on the network (For example,
LAN, CATV, FTTx, Access, Metro, or Long Haul)
JDSU CommTest provides the tools and services
to ensure the performance of your fiber optic
system!
We are the World Leader in fiber video inspection
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Making IBYC Easy
ESSENTIALS TOOLS in ONE DEVICE
Easy-use optimizes workflow
procedures
Promotes proper fiber
handling practices
Integrated functions and
features eliminate switching
between different devices
- Inspect bulkhead with probe
- Inspect patch cord with
integrated patch cord
microscope (PCM)
HP3-60-P4 Display System with FBP Probe
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- Test power measurement
with integrated power meter
HP3-60 Display System
INTEGRATED INSPECTION & TEST
Patch Cord Inspect Input
The new HP3-60 display
system combines fiber
inspection and optical power
measurement into a single
seamless handheld device.
Input for Power Meter
Probe Input
(for bulkhead inspection)
Power Meter Display
This unique combination
makes the HP3-60 system the
industry’s only solution for
inspecting and testing fiber
networks with one handheld
device, enabling increased
workflow efficiency and
decreased total inspection and
test time.
Power Meter Controls
1.8 in. Fiber Display
Power Button
A/B Switch
(toggle between patch
cord and bulkhead fiber
view)
Focus Control
Low Battery Indicator
FIT-HP3-60-P4
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Full Range of Optical Inspection and Test Solutions
Fiber Cleaning and Inspection
– Handheld Microscopes
– Probes
– Automated Analysis
Visual Fault Locators
PocketClass Light Sources and Power Meters
– SM, MM
– Various Wavelengths
Smart Optical Testers
– Light Sources and Power Meters
– Loss Test Sets
– Optical Return Loss Meters
Services
– Training/Certification
– On-Site Testing incl. Fiber Characterization
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