L2 OPTICAL FIBER

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L2OPTICAL FIBER CABLE TYPES PROPERTIES
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The Whole View
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Contents

• Basic Principle (Review)
• Fiber Specification
• Types of Fiber Material
• Fiber Optic Cable
• Cable Design Criteria
• Choosing a Cable
• Typical Network Devices
• Summary

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Basic Principle (Review)
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Basic Specification

• Core/ Cladding Diameter
• Attenuation Coefficient
• Numerical Aperture (NA)
• Potential Bandwidth
• Chromatic Dispersion/ PDL/ PMD Coefficient
• Application

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Fiber Specifications
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Types of Fiber Material
Glass Fiber Optic Cable

• lowest attenuation and comes at the highest cost
• most wide spread use
• most popular with link installers

Plastic Fiber Optic Cable

• highest attenuation but comes at the lowest cost.
  
• pioneered in Japan principally for use in the
  automotive industry.
• just beginning to gain attention in the premises
  data communications market

Plastic Clad Silica (PCS)

• has an attenuation that lies between glass and
  plastic.
• has considerable plasticity that makes connector
  application difficult
• all of this makes this type of fiber optic cable
  not particularly popular with link installers.

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Some Of ITU-T Standard (G-Series) Related to The
Fiber Optic Field
G.650 G.655 Optical fiber cables G.911
G.911 Parameters for optical fiber cable
systems G.971 G.977 Optical fiber submarine
cable system G.981 G.995.1 Optical line
systems for local and access networks
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FIBER OPTIC CABLES
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Fiber Optic Cable

• A complete assembly of fibers, strength members
  and jacket.
• Lots of different types, depending on the number
  of fibers and how and where it will be installed
• The choice will affect how easy it is to install,
  splice or terminate and most important, what it
  will cost

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Fiber Optic Cable Type of Cable
Indoor
Outdoor
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Indoor Optic Fiber Cable

• Cable is installed in a building or campus
• Involves short lengths, rarely longer than a few
  hundred feet, with 2 to 48 fibers per cable
  typically.

Duplex
Simplex
Distribution
Type of Indoor Cable
Breakout
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Simplex Cable

• One fiber, tight-buffered (coated with a 900
  micron buffer over the primary buffer coating)
  with Kevlar (aramid fiber) strength members and
  jacketed for indoor use.
• The jacket is usually 3mm (1/8 in.) diameter.
• Zipcord is simply two of these joined with a thin
  web.
• costly for patch cord and backplane applications.

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Simplex Cable
Jacket
Strain relief
Semi-tight tube
Fibre
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Duplex (Zipcord) Cable

• Zipcord is simply two of simplex, joined with a
  thin web
• It's used mostly for patch cord and backplane
  applications

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Distribution Cable
Contain several tight-buffered fibers bundled
under the same jacket with Kevlar strength
members and sometimes fiberglass rod
reinforcement to stiffen the cable and prevent
kinking. Small in size, and used for short,
dry conduit runs, riser and plenum applications.
The fibers are double buffered and can be
directly terminated, but because their fibers are
not individually reinforced, these cables need to
be broken out with a "breakout box" or terminated
inside a patch panel or junction box
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Distribution Cable
Termination Box (TB)
Splice tray
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Breakout Cable

• Made of several simplex cables bundled together.
• A strong, rugged design, but is larger and more
  expensive than the distribution cables.
• Suitable for conduit runs, riser and plenum
  applications. Because each fiber is individually
  reinforced, this design allows for quick
  termination to connectors and does not require
  termination box.
• More economic where fiber count isn't too large
  and distances too long, because is requires so
  much less labor to terminate.

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Breakout Cable
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Fiber Optic Connector
FC stands for Fixed Connection. It is fixed by
way of threaded barrel housing. FC is the
optical fibre connector standard for Nippon
Telephone Telegraph (NTT) installations,
developed with Nippon Electric Co. (NEC).
LC stands for Lucent Connector. It is a small
form-factor optical fibre connector.
SC stands for Subscriber Connector. SC is the
optical fibre connector developed by NTT, Japan.
It is frequently used for newer network
applications such as DWDM and is widely used in
singlemode systems for its performance.
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Fiber Optic Connector
MU is a small form of SC connector which was
developed by NTT, Japan. The MU connector looks
a miniature SC with a 1.25 mm ferrule. It is a
popular connector type in Japan.
E2000 stands for Euro 2000 connector. It was
developed by Diamond in 2000.
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Fiber Optic Adaptor
An adapter is a mechanical device used to align
and join two or more fibers with different
connection types.
FC
SC
E2000
MTRJ
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Fiber Optic Connector Polishing Type
PC (Physical Contact) is the point at which the
surface of one glass surface meets another in
order for light to be transmitted. Typically
this occurs within the ferrule to ensure
concentricity and polish.
UPC (Ultra Physical Contact) is specific to
singlemode applications, referring to the endface
geometry of a connector ferrule as well as
performance characteristics (-55dB Return Loss).
APC (Angle Physical Contact) is specific to
singlemode applications where the endface of the
ferrule is actually cut and polished to an 8
degree angle. This increases mateable surface
area as well as return loss performance (-65dB).
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Why Optical Fiber Connector Cleaning Is Important?
A cleaning standard for optical fiber connectors
could save industry millions of dollars
annually. Contamination of connector end faces
in the form of something as simple as dust
particles or fingerprints can change light
propagation through the fiber, degrading device
performance and causing data errors. Cleaning
the fiber optic equipment is one of the most
basic and important procedures for maintaining
fiber optic systems Clean fiber optic components
are a requirement for quality connections between
fiber optic equipment.
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Root Cause Analysis

• Most of the optical connector problems were due
  to connectors ferrule end-face contaminated.
• The contaminant particles can causes error by the
  reason as follows
• A particle which partially or completely
  covered core will reflect back the
  optical signal toward laser source. This can
  cause the laser system become unstable.
• A particle which deposited on the fiber core
  can absorbs light and coverts it into heat.
  Optic fiber surface can be damaged by this heat.
  
• Dust particles trapped between two fiber faces
  can scratch the glass surfaces. It also can
  cause an air gap or misalignment between the
  fiber cores which will significantly degrade the
  optical signal.
• The high loss patch cord also may due to ferrule
  end-face damaged (starched or in extreme cases
  cracks in the glass cladding and core).

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How Optical Fiber Connector End Face Can Be
Contaminated?
A. In-proper handling of patch cord during
installation.

• During installation the connector in proper
  manner during inserting ferrule into adaptor.
  This can cause the ferrule end-face mates with
  adaptor surface which may contaminate.
• The ferrule end-face was touched contaminated
  surface (such as human body, cloth etc)
  accidentally.
• The ferrule protective end cap was not installed
  during installation before mated with adaptor.

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B. Wrong connector / adaptor cleaning technique
or procedure was applied.
Wet Cleaning Technique

• The alcohol used is not isopropyl 99.
• The residual alcohol is not remove properly if
  the alcohol is allowed to evaporate of the
  ferrule, it can leave residual material on the
  ferrule end face.
• The cleaning material / cotton is sometimes
  reused.
• No inspection carried out after cleaning process.
  

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Dry Cleaning Technique

• The fiber was scrubbed against the fabric.
• The fiber was cleaned over the same fabric
  surface more then once.
• No inspection carried out after cleaning process.

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Optical Fiber Connector Cleaning - Tools
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Optical Fiber Connector Inspection Tools
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Optical Fiber Connector End Face Image
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Fiber Distribution Frame (FDF)
Pigtail (Distribution cable)
Patch cord
Line Side
Equipment Side
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Outdoor Cables

• Loose Tube Cable
• Overhead Cable
• Armored Cable (Direct Burial)
• Duct Cables (Indirect Burial)
• Submarine Cable

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• Loose Tube Cable

These cables are composed of several fibers
together inside a small plastic tube, which are
in turn wound around a central strength member
and jacketed, providing a small, high fiber count
cable.
Fiber
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• Loose Tube Cable

It can be used in conduits, strung overhead or
buried directly into the ground. Since the
fibers have only a thin buffer coating, they
must be carefully handled and protected to
prevent damage.
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Slotted Ribbon Fibre Cable
This cable offers the highest packing density,
since all the fibers are laid out in rows,
typically of 12 fibers, and laid on top of each
other. Since it's outside plant cable, it's
gel-filled for water blocking.
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• Slotted Ribbon Fibre Cable

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Armored Fibre Cable
Cable installed by direct burial in areas where
rodents are a problem usually have metal
armoring between two jackets to prevent rodent
penetration. The cable is conductive. Thus, it
must be grounded properly.
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Overhead Fibre Cable
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Optic Fibre Joint Closure
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E. Cable Design Criteria

• Pulling Strength
• Water Protection
• Fire Code Ratings

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Pulling Strength

• Some cable is simply laid into cable trays or
  ditches, so pull strength is not too important.
• But other cable may be pulled thorough 2 km or
  more of conduit. Even with lots of cable
  lubricant, pulling tension can be high.
• Most cables get their strength from an aramid
  fiber (Kevlar is the duPont trade name), a unique
  polymer fiber that is very strong but does not
  stretch - so pulling on it will not stress the
  other components in the cable.
• The simplest simplex cable has a pull strength of
  100-200 pounds, while outside plant cable may
  have a specification of over 800 pounds.

OD Outer Diameter Load Load is due to pulling
force
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Water Protection

• Outdoors, every cable must be protected from
  water or moisture.
• It starts with a moisture resistant jacket,
  usually PE (polyethylene), and a filling of
  water-blocking material.
• The usual way is to flood the cable with a
  water-blocking gel.
• A newer alternative is dry water blocking using a
  miracle powder - the stuff developed to absorb
  moisture in disposable diapers. Check with your
  cable supplier to see if they offer it.

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Fire Code Ratings

• Every cable installed indoors must meet fire
  codes.
• That means the jacket must be rated for fire
  resistance, with
• ratings for general use, riser (a vertical cable
  feeds flames more
• than horizontal) and plenum (for installation in
  air-handling
• areas. Most indoor cables us PVC (polyvinyl
  chloride) jacketing
• for fire retardance.
• All premises cables must carry identification and
  flammability
• ratings per the NEC (National Electrical Code)

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NEC Rating
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F. Choosing A Cable

• With so much choice in cables, it is hard to
  find the right one.
• The table below summarizes the choices,
  applications and advantages of each

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Relationship Between Outdoor Indoor Cable
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• Installation of Outdoor Cable

Erection of Aerial Cable
Pulling of Underground Cable (Duct)
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• Erection of Aerial Cable

The length of cable laid depends upon the span
lengths, terrain and other field condition.
In straight sections, a maximum of seven spans or
approximately 350 m shall usually be laid at any
time.
Two method of placing the cable drum for cable
laying -
The cable drum is placed on vehicle/cable
trailer. As the vehicle moves, the pulling end
of the cable is carefully uncoiled and laid onto
the ground. It must not be dragged along the
road or run over by any vehicles.
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• Erection of Aerial Cable

Place the cable drum at the midpoint of the
section. Carefully pull the cable towards one of
the splice location. Uncoil the balance of the
cable in the drum in form of a Figure of 8 for
pulling to opposite direction.
Cable Drum
Pulling Direction
1m
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• Erection of Aerial Cable

The cable is raised and placed onto the pulley
which is attached to all the poles.
Terminate the free end of the cable and ensure
sufficient length is available for testing and
splicing.
Fix the cable to poles. Cable clamps are used to
hold the cable by clamping the bearer wire.
Support hooks (S hook) are used to hang the
cable via the cable clamp onto the bracket
tubular pole.
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• Erection of Aerial Cable

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• Installation of Underground Cable

The length of cable laid depends upon the span
lengths, terrain and other field condition.
In straight sections, a maximum of seven spans or
approximately 350 m shall usually be laid at any
time.
Two method of placing the cable drum for cable
laying -
The cable drum is placed on vehicle/cable
trailer. As the vehicle moves, the pulling end
of the cable is carefully uncoiled and laid onto
the ground. It must not be dragged along the
road or run over by any vehicles.
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• Installation of Underground Cable

Figure 8
Cable Drum
Duct
Manhole
Cable
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• Installation of Underground Cable

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