definition of fibre optic

8/10/2019 Definition of Fibre Optic

1/28

Definition of Fibre Optic

Fibre Optic is a thin strand of highly transparent glass or sometimes plastic that guide light.

It is used as a medium for carrying information from one point to another in the form of

light. A basic fibre optic system consists of a transmitting device, which generates the light

signal; an optical fibre cable, which carries the light; and a receiver, which accepts the light

signal transmitted. The fibre itself is passive and does not contain any active properties

Basic Construction of Optical Fibre.

1.Core:

The centre of the fibre through which the light is transmitted.

2. Cladding:

The outside optical layer of the fibre that traps the light in the core and guides it

along and even through curves.

3. Buffer coating or primary coating:

A hard plastic coating on the outside of the fibre that protects the glass from

moisture or physical damage.

Fiber optic cable functions as a "light guide," guiding the light introduced at one end of the

cable through to the other end. The core and cladding are manufactured together as a single

piece of silica glass. The core regions refractive index (or optical density) is greater than the

Core

Cladding

Coating

Core8.3m

Cladding125m

Coating250m

Cross Sectional View of a Single Mode Fiber Side View of a Single Mode Fiber


2/28

cladding layer. The glass does not have a hole in the core, but is completely solid throughout.

The light is "guided" down through the core. The cladding traps the light in the core using an

optical technique called "total internal reflection. The third section of an optical fibre is the

outer protective coating called the "primary buffer coating". This coating is typically an

ultraviolet (UV) light-curedacryl ateapplied during the manufacturing process to provide

physical and environmental protection for the fibre. During the installation process, thiscoating is stripped away from the cladding to allow properterminationto an optical

transmission system.

Constructional Details of Fibre Optic Cable

Rip Cord

Water Blocking Material

(Jelly)

Outer Sheath (Jacket)Double Layer for Direct

Buried Single Layer

for Duct Cable

Steel for !rounding

"hread #aper

Dielectric Strength$le%ent (&e'lar)

Central Strength Me%ber

Optical ibre

!el*illed Buffer "ube

Outer Sheath

(Jacket)

Steel heath for

!rounding

Dielectric Strength

$le%ent (&e'lar)

"hread and #aper

!el illed

Buffer "ubeCentral Strength

Me%ber

Optical fibre
http://www.corningcablesystems.com/web/news/dsprgall.nsf/ehtml/glossary#acrylatehttp://www.corningcablesystems.com/web/news/dsprgall.nsf/ehtml/glossary#terminationhttp://www.corningcablesystems.com/web/news/dsprgall.nsf/ehtml/glossary#acrylatehttp://www.corningcablesystems.com/web/news/dsprgall.nsf/ehtml/glossary#termination


3/28

Types of Fiber Optic Cables

There are two types of fiber optic cable commonly used:

1. Multi Mode Cables

2. Single Mode Cables

1. Multi Mode Cables

Over the years a variety of core sizes have been produced but these days there are only two

main sizes for Multimode fibers. These cables are most widely used in data networks. The

numbers 50/125 & 62.5/125 represent the diameters of the fibre core and cladding, these are

measured in microns which are millionths of a metre.

2. Single Mode Cable

Single Mode cable has a core diameter of 8.3 to 10 microns. It is the most commonly

used cable in Telecommunication for transmission systems. The numbers 8.3/125

represent the diameters of the fiber core and cladding,

Note:Both multimode and single mode fibres have an outside diameter of

125 microns - about 5 thousandths of an inch - just slightly larger than

a human hair.


4/28

Definitions of Terms used in Fibre Optic Cable

1. Terminations

Patch panels:-

Provides a centralized location for patching fibres, testing, monitoring and restoring

cables.

Connector:

A non-permanent device for connecting two fibres or fibres to equipment where they

are expected to be disconnected occasionally for testing or rerouting. It also provides

protection to both fibres.

Ferrule:

A tube which holds a fibre for alignment, usually part of a connector

LC Connector

LC stands for Latched Connector and its interconnect is based upon the RJ-45

telephone interface. The LC Connector uses Zirconia ceramic ferrules in a free-

floating and pull proof design.

SC connector

SC Stands for Single Coupling. It is Square shaped snap-in connector that latches

with a simple push-pull.The SC connector has the advantage (over ST) of being

duplexed into a single connector clip with both transmit/receive fibres.

MU Connector

The MU stands for Miniature Unit fibre-optic connector, which features compact size,high packaging density, and high performance and a simple push-pull design. The

MU connector ferrules are half the size of the standard FC, SC connectors and are

excellent for high density installations.


5/28


6/28

For long cable runs outside, the point where cables are spliced, sealed up and buried

in the ground, put in a vault of some kind or hung off a pole.

Splice panels

Connect individual fibres from cables to pigtails

Splice:

A permanent joint between two fibres

Mechanical Splice:

A splice where the fibres are aligned by mechanical means

Fusion Splice:

A splice created by fusing two fibres together

Fusion Splicer:

An instrument that splices fibres by fusing them, typically by electrical arc.

3. Measurements

Attenuation:

The reduction in optical power as it passes along a fibre, usually expressed in decibels

(dB).

Bandwidth:

The range of signal frequencies or bit rate within which a fibre optic link or network

will operate.

Chromatic dispersion:

A property of optical fibre due to which different wavelengths travel at different

speeds and arrive at different times, resulting in spreading of a pulse in an optical

waveguide.

Decibels (dB):


7/28

A unit of measurement for optical power which indicates relative power. A -10 dB

means a reduction in power by 10 times.

dBm:

Absolute Power, Optical power referenced to 1 milliwatt.

Nanometer (nm):

A unit of measure used to measure the wavelength of light (meaning one one-

billilonth of a meter)

Optical Loss:

The amount of optical power lost during transmission of through fiber, splices,

couplers, etc. expressed in dB.

Optical Power:

It is measured in "dBm", or decibels referenced to one miliwatt of power. While loss is

a relative reading, optical power is an absolute measurement, referenced to

standards. Absolute power is measured to test transmitters or receivers and relative

power to test loss.

Optical Return Loss, back reflection:

Light reflected from the cleaved or polished end of a fibre caused by the difference ofrefractive indices of air and glass.

Power budget:

The total amount of power lost in the link. Often used in terms of the maximum

amount of loss that can be tolerated by a given link.

Polarization Mode Dispersion:

The spreading of a pulse in an optical waveguide by virtue of different light paths

lengths is called Modal dispersion.

Refractive index:

A measure of the speed of light in a material, a property of optical materials that

relates to the velocity of light in the material


8/28

Scattering:

The change of direction of light after striking small particles that causes loss in

optical fibres and is used to make measurements by an OTDR

Wavelength:

A term for the color of light, usually expressed in nanometers (nm) or microns (m).

Fiber is mostly used in the infrared region where the light is invisible to the human

eye.

4. Test Equipment

Optical Power Meter:

An instrument that measures optical power from the end of a fibre

Laser Source:

An instrument that uses a laser or LED to send an optical signal into fibre for testing

loss of the fibre

Optical Loss Test Set (OLTS):

A measurement instrument for optical loss that includes both a power meter and

laser source

Reference Test Cables:

Short, single fibre cables with connectors on both ends, used to test unknown cables.

Mating Adapter:

Also called couplers, allow two cables with connectors to mate.

Optical Microscope:

Used to inspect the end surface of a connector for dirt.

Fibre Optic Splicing

There are two methods of fibre optic splicing, fusion splicing & mechanical splicing.

Mechanical splicing is usually carried out for emergency restorations whereas fusion splicing


9/28

is done for permanent repairs of damaged cable or to connect the reels of cable during

installation

Mechanical Splicing:

Mechanical splices are simply alignment devices, designed tohold the two fibre ends in a precisely aligned position thus enabling light

to pass from one fibre into the other. (Typical loss: 0.3 dB)

Fusion Splicing:

Fusion splicing is the joining and fusing of two fibres by placing them between two electrodes,

and discharging an electric arc over the fibres. This splice technique is non-reflective.Fusion

splicing machine is used to precisely align the two fibre ends then the glass ends are "fused"

together using electric arc. This produces a continuous connection between the fibres

enabling lower loss and less back reflection than mechanical splicing because the resulting

fusion splice points are almost seamless. (Typical loss: 0.1 dB)
http://var/www/apps/conversion/tmp/scratch_5/fiber/32531.html


10/28

+o*+ik Stripper

Cutter

Cable

cutter

,and -ir

Blo.er

-ir Jet

/opropyl -lcohol

S.ab

ibre Stripper

Round Jacket Stripper

Longitudinal

Cable Jacket

Slitter

Scior

".i00er

Buffer "ube

Stripper

Buffer "ubeStripper

Cleaning

"ape


11/28


12/28

2.Cleaning

After the coating is removed, clean the fibre withspecially designedisopropyl alcohol

wipesso that the fibre squeaks.

3.Cleaving

A good cleave is the key to obtaining a good splice. Use cleaver to cut the fibre. After

cleaving do not touch or clean the fibre.

4.Splicing

The fibre is now ready to be spliced mechanically or Fusion. Insert the fibre carefully

in the mechanical splice or in the fusion splicer for splicing. While inserting in the

mechanical splice make sure that fibre is inserted directly in the groove and do not

touch any other surface. Fusion splicer will automatically align and fuse the fibre.

5.Protection.

In case of fusion splicing cover the splice with heat shrink sleeve and place it in the

heater, for mechanical splice carefully close the mechanical splice.

6.Organizing.

Organize the fibre in the enclosure properly Make sure that organising do not cause

Micro-bending.

Testing

Cables need to be tested forcontinuity, end-to-endlossand any other potential problems.

For long outside plant cables with intermediate splices, all individual splices need to be

verified with an OTDR, since that's the only way to make sure that each one is good. Within

the network testing forpoweris necessary as power is the measurement that tells whether

the system is operating properly.

Tools and test equipment for the job.

1.Source and power meter, optical loss test.

2.Reference test cables.

3.Cleaning materials - lint free cleaning wipes and pure alcohol.

4.OTDR and launch cable for outside plant jobs.


13/28

Measurement of Optical Power & Loss

There is a difference between the power coupled into a component like a cable or a connector

and the power that is transmitted through it. This difference is what we call optical loss and

defines the performance of a cable, connector, splice, etc.

Measuring power

Power in a fibre optic system is like voltage in an electrical circuit. To measure power,

attach the meter to the cable that has the output you want to measure. Turn on the

transmitter/source and note the power the meter measures.

Testing Loss

Following two methods are used to measure loss. Optical Loss Test Sets houses a light source

and power meter in the same unit. For both methods two units of loss test sets (one at each

end of the fibre under test) are required.

Single Ended Loss

This test is initiated from one end and results are displayed at both units.

Double Ended Loss

In this test Laser source is initiated from one end and the result is displayed at the

other end.

Both test method measure the loss of two ODF connectors (one on each end), the loss of cable

and splices in between. Most commonly FASTTEST setup method is used for loss testing.

Fiber Optic Linkunder Test

Optical

Loss

Test Set

Optical

Loss

Test Set

Transmitter Receiver

Test

Patch

Cord

Test

Patch

Cord

FASTTEST SETUP


14/28

Prior to perform Loss test measurement, a reference measurement must be stored in both

units. The reference measurement includes the loss caused by the test setup components

including test jumpers. The unit will store a reference reading of power level at the end of

test jumper. This reference measurement is subtracted from the overall loss so the final lossresult represents the loss of system under test alone.

Referencing Optical Loss Test Unit

There are two referencing methods in practice for Loss test sets and both results in accurate

loss measurement.

1.Loop-back Method with only one test jumper

2.Side-by-Side Method with two test patch cords and a mating adapter.

1. Loop back Method

The main advantage of the loop back referencing method is that there is no need to bring

both units at same location. This is performed by connecting a single test patch cord from theunits Source Port (FASTTEST Port) to Detector Port.

After performing the loop-back reference, simply disconnect the test patch cord from

the Detector Port and connect it to the ODF of Fiber link Under Test.

Optical

Loss

Test Set

Source of FASTEST port

not to be disrupted once

the reference is set.

etector Port! isconnect

this end and connect to OF

of FO lin" under Test


15/28

It is very important not to disconnect it from the source port (FASTTEST Port)

because the amount of light coupled or injected into the test patch cord varies from

one connection to another.

If the test patch cord is disconnected from the source port, it is required to repeat the

references.

The loop-back test is performed individually on each of the two units.

An important advantage of the loop-back method is that it automatically takes into

account the loss of the test patch cord and Mating adapters, allowing a true

measurement of the fiber itself.

2. Side-by-Side Method

To perform the side-by-side reference procedure,two test patch cord are connected via a

Mating adapters and then connect the test patch cord ends to the Source Port (FASTTEST

Port) on one unit and the Power Meter (Detector Port) on the other.

When using the side-by-side reference method, both units must be brought to a

common site to take the appropriate references.

Optical

Loss

Test Set

FastTest Port

#ot to be disrupted once

the reference is set

Optical

Loss

Test Set

etector Port $

Po%er &eter Port

&atin' Adapter

isconnect here to connect to

OF of FO lin" Under Test

ReceiverTransmitter


16/28

Once the side-by-side reference is performed, disconnect the test jumpers at the

Mating Adopter and connect both test jumpers to the ODF of Fiber Link Under Test.

Much like the loopback reference, it is very important not to disconnect the test

jumper from the source port as the amount of light coupled or injected into the test

patch cord will vary from one connection to another. If the test patch cord isdisconnected from the source port (FASTTEST Port), it is required to repeat the

reference.

Note: Before measuring optical loss with an automated OLTS, referencing is a

crucial procedure that should be performed before every test session.

Single Ended Loss Measurement

To measure the Single-ended loss only launch cable is used and the loss is measured by

mating the FO cable under test to the reference launch cable and measuring the power out atthe far end with the meter. Following losses are measured.

1.The loss of the connector mated to the launch cable.

2. The loss of fibre, splices or other connectors in the cable you are testing.

Double Ended Loss Measurement

To measure the double-ended loss in addition to the reference launch cable a receive cable is

also attached to the meter. In a double-ended loss test, we attach the FO Cable Under Test

between two reference cables, one attached to the source (FASTTEST Port) and other to the

power meter (Detector Port). This way, we measure two connectors' losses, one on each end,

plus the loss of all the cable or cables in between.

Power Budget

Losses occur at many points in a fibre optic system. We have to ensure that the light source

launches enough power into the fibre to provide enough power at the receiver. The receiver

has limited sensitivity.

Transmitter output - Receiver input = Losses + Margin (All calculations are done in dB)

Types of Loss

For single mode fiber cable with two most commonly used wavelengths 1310 nm and 1550

nm


17/28

The attenuation measurement will vary depending upon which wavelength is in use.

Attenuation is measured in dB and is quoted as attenuation in dB/km.

Fiber Loss Variables

Attenuation:

All fiber has losses from absorption and back reflection of the light caused by

impurities in the glass. Attenuation is a function of wavelength and needs to be

specified or measured at the wavelength in use.

Modal Dispersion:

The higher the data rate, the shorter the distance the signal can travel before modal

dispersion creates an inability to accurately detect the signal (i.e. a "1" from a "0").

Dispersive Losses:

Another dispersion effect, which causes pulse spreading, and limits distance is

chromatic dispersion, where the broader spectrum of light can result in varying

travel times for different parts of a light pulse.

Splices:

Although small and often insignificant, there is no perfect loss-less splice. Many

errors in loss calculations are made due to a failure to include splices. Average splice

loss is usually less than 0.1 dB.

Connectors:

Like splices, there is no perfect loss-less connector. It is important to note that even

the highest quality connectors can get dirty. Dirt and dust can completely obscure a

fiber light wave and create huge losses. A 0.5 dB loss per connector is commonly the

worst case scenario assuming a cleaned and polished connector is used. There will

always be a minimum of two connectors per fiber segment, so remember to multiply

connector loss by two.

Safety Buffer:


18/28

It is common to add a loss as a design margin. Allowing 2 - 3 dB of loss can take fiber

aging, poor splices, temperature and humidity, etc., into account and ensure a solid

system.

NOTE:

To determine minimum/maximum losses and maximum distances you need to

identify all of the above variables. Failure to identify even one of these variables can

create potential problems

Fiber Terminology

Calculating Power Budget

There are commonly two different calculations you require with fiber. Each assumes you have

known values for different sets of variables.

One calculation determines the maximum signal loss across a piece of pre-existing

fiber (Link Loss)

The other calculation determines the power budget of a fiber link.

The first calculation below will calculate link loss through a known length of fiber.

Second calculation below Calculate the power budget of the link (i.e. maximum signal loss is

simply the sum of all worst-case variables within your fiber segment.)

Table( Attenuation Criteria

Optical

Fiber Type

Loss/Km Loss

in dB Connector Splice

1310nm 1550nmIn dB

Single Mode 0.35 0.23 0.50 0.09

1. Link Loss Calculation


19/28

The measured value of attenuation of a FO link should not exceed the sum of

allowable attenuation of each component.

These components are: -

The Fiber Optic cable The FO connectors

The Splices

Link Loss (dB)=Cable Loss+Connector Loss+Splice Loss

Cable Loss (dB) = Cable length (Km) x Attenuation Coefficient

(db/Km)*

Connector Loss (dB) = Number of Connector Pairs x Connector Loss

(dB)*

Splice Loss (dB) = Number of Splices x Splice Loss (dB)*

(*) : from above table for Attenuation Criteria

). Optical Po%er *ud'et Calculation

Optical Power Budget=(Fiber Attenuation x km)+(Splice Attenuation x No

of splices)+(Connector Attenuation x No of connectors)+(Safety Margin)


20/28

OTDR Trace Analysis

Non-Refective

Event(Fusion Splice,Bend)

Non-RefectiveEvent

(Micro Bending)

Noise

Out ut End-F!ceRefection

"n-ut End-F!ceRefection

Dead

Zone#$n!%ic

R!nge Refective Event(&onnector, Mec'!nic!lSplice)

#ist!nce(%)

%

dB%

End

to

End

Loss

ReflectiveEvent

Dead Zone

Reflective

Event Loss

DeadZone

Launc

h Level

Non-

Reflectiv

e Event

Loss

Non-

Reflective

Event Loss

caused by

Micro-

Bending or

Bad Splice


21/28

There are four main settings that the technician must set on the OTDR beforeOTDR testing.

Those are Wavelength, Index Of Refraction, Pulse Width and Distance.

1. Wavelength-

The behaviour of an Optical system is directly related to the wavelength of transmission. Not

only Optical fibre will exhibit different loss characteristics at different Wavelengths, but

splice loss value also differ at different wavelengths. In general fibre should be tested with

both wavelengths i.e. 1310 and 1550nm for single mode fibres. If testing is only to be

performed at one wavelength it should be done with 1550nm considering the following points

1550nm will see longer distances down the fibre due to the lower attenuation as

compared t0 1310nm.

1550nm is more sensitive to losses incurred by bending during installation and

organising of fibres in the splice enclosures after splicing.

2. Index Of Refraction-

The index of refraction sets the OTDR to the proper speed of light for a particular fibre link

being tested.

Changing the IOR value will change the distances to events on the OTDR trace, andalso the overall length of the fibre.

The IOR of a particular fibre is usually provided by the manufacturer.

3. Pulse Width or Duration-


22/28

This is another setting that must be selected to receive the clearest information from the

OTDR trace. The length of time that the OTDR's laser is turned on is called the "pulse

width". As the OTDR turns the laser on and off, the duration of the laser being on results in

a pulse of a certain length.

Shorter pulse widths provide better traces of events that are close together, as theshorter pulse widths will have shorter dead zones after reflective events. However,

short pulse widths will result in a noisy, hard to interpret trace for long distance fibre

link, as the OTDR process weaker returned signals.

Long pulse widths means more light energy is injected in the fiber. The more light

injected means the more light is reflected back from the fiber to OTDR. It causes

longer dead zones, and reduces resolution of events that are close to each other.

Long Pulse width is therefore used to see long-distance down a cable.

The General Rule to set Pulse width is:

Short Fibre Link = Short Pulse Width

Long Fibre Link = Long Pulse Width

Shorter pulse widths can be used on longer fibre links to give greater detail to events

close to the OTDR and for fault analysis.

4. Range or Distance-

The range on an OTDR is the maximum distance that OTDR will acquire data samples. This

parameter is generally set at twice the distance of of the end of the fibre.

Note:

Neglecting to set any of these parameters properly can result in erroneous reporting by

the OTDR.

Dead Zone

The OTDR is designed to detect the back scattering level all along the fibre link. It measures

the back scattered signals which are much smaller than the signal sent to the fibre. When

there is a strong reflection then the power received at the OTDR is much higher than the

backscattered power which saturates the OTDR. OTDR requires time to recover from the


23/28

saturated condition. During this time OTDR cannot detect the backscattered signal

accurately. The length of fibre which is not fully characterized during the recovery period is

termed as dead zone.

This affect is similar to the one when we are driving a car at night and that another cars

headlight dazzle our vision momentarily.

The dead zone depends on the pulse width, the reflectance, the loss and the location.

Cleaning of Connectors

Proper cleaning of connectors is very important. The core diameter of a single-mode fiber is

only about 9um. This generally means you cannot see streaks or scratches on the surface.

Follow the under mentioned procedure to clean the connector.

.

1.Clean the connector by rubbing it on cleaning tape or a new, dry cotton swab using a

small circular movement.

2.Blow away any remaining lint with compressed air.

If the connector has greasy dirt on its tip follow the following procedure.

1.Take a new Moisten cotton swab with isopropyl alcohol.

2.Clean the connector by rubbing the cotton swab over the surface using a

small circular movement.

3.Take cleaning tape and rub it in small circular motion to remove the alcohol

dissolved sediment and dust.

4.4. Blow away any remaining lint with compressed air.

Do Not Forget to clean the connector with cleaning tape

after cleaning it with isopropyl alcohol swab.

L

Specifications and procedures for Cable Installation

1. Cable Depth:


24/28

The depth at which buried cable can be placed will vary with local conditions i.e

Type of soil. However fiber optic cable must be buried at a minimum depth of 80

cm.

Table showing depth of Buried Fiber Optic Cables*

Location Depth

Soft Soil 80 ~ 120 Cm

Hard Soil / Rock Soil Minimum 80 cm

Road Way crossing Minimum 110 cm

Under mentioned diagram shows the typical layout of Direct Buried cable.

12 c%

12 c%Soft Sand

Soft Sand

32 452 c%

52 4612 C%

Min 6Meter

Back

filling

ront 7ie.

iber OpticCable

Soft Sand

Soft Sand

Back filling

Warning

"ape

Side 7ie. of "rench

Soft Sand

Le'end

Back filling

8nditurbed$arth


25/28

In certain installation areas, for example, rights-of-way with limited access (public highways,

private property boundaries, water ways, Culverts and under the bridges, cable must be

buried in a duct and if such installations are done after the installation of cable, Fiber Optic

cable must be protected in the affected area with PVC pipe, iron barring and concrete.

Cable must be protected at all constructions site such as unimproved roads, streets and alleys

that may later be paved or hard surfaced9*Deviations from desired depthshould be noted on drawings

CAUTION:

Depths less than those specified may expose the cable to erosion or excavation

damage.

In conditions where these depths are not feasible or permitted Iesser depth is

permissible provided additional protection inthe form of concrete casements

or sub duct is provided.

Splice Points

Splice point locations must be chosen carefully for easy access for future maintenance.

Splicing must always be done in the car and in order to reach splicing vehicle, ensure a

minimum of 10 ~ 15meters of extra cable on both cable ends at each splice point

At Hand Holes and Man Holes place the cable slack vertically (in line with the cable

route)

In the case of a buried splice point, coil and bury the slack Horizentally .Figure 5

Hand hole

20 Cm

Warning Tape

10~15M slack

Splice Pit2 x 2 Meter

80~120 cm

Splicing Van


26/28

Points To Remember

Safety First!

Small scraps of glass i.e. cleaved-off ends of the fibres being terminated or

spliced is very dangerous! They are extremely sharp and are basically glass

needles that will easily penetrate flesh then break off and become nearly

impossible to remove. Once in the body it will likely become infected. If they

get into the eyes, they are very hard to flush out. Don't even think about what

happens if you eat one. Always follow these rules when working with fibre.

Find and dispose-off all cut fibre fragments immediately after cutting.

Buried Splice #ointMan ,ole,and ,ole

Buried !intT!p Vie"

20 cm

10cm

S!#t Sand

S!#tSand

$0 ~80 cm

80 ~120

Min 2Meter

Back#illing

%r!nt Vie"

WarningTape10cm

Tiles

&irect BuriedSplice


27/28

Dispose-off all scraps properly.

Handle cut fibre fragments with tweezers only

Do not drop them on the floor where they will stick in carpets or shoes and be carried

elsewhere.

It is your responsibility to ensure that no fibre fragments escape and injure

someone. If you lose a fibre fragment you must look until you find it.

5.Fiber fragments can stick to the cover of the cleaver. Move slowly when opening the

cover. Always look on the inside of the cover if you dont see your fragment on the

shelf of the cleaver.

If you cant find your fragment, get more light on the subject and work area.

Do not move the cleaver until the fragment has been found.

Use a magnifying glass if you need to butFIND THAT FRAGMENT.

6.Do not eat or drink anywhere near the work area.

The light in Transmission system is infrared and you can't see it therefore always be

careful with your eyes.

When using a fibre optic microscope.NEVERlook into a fibre unless you personaly

confirm nolight is present. Use a power meter to check it.

Zero Tolerance for Dirt

With fibre optics, our tolerance to dirt is near zero. Airborne particles are about the size of

the core of SM fibre- they absorb lots of light and may scratch connectors if not removed! Dirt

on connectors is the biggest cause of scratches on polished connectors and high loss

measurements!

Try to work in a clean area.

Always keep dust caps on connectors & patch panels when not in use. Keep them

covered to keep them clean.

Use lint free pads and isopropyl alcohol to clean the connectors.


28/28

After cleaning with isopropyl alcohol swab do not forget to clean it with the Cleaning

Tape.

Tools and Materials

Make sure to have the proper tools for the job.

Confirm that all tools are in good shape before you head out for the job. This includes

all the cable tools and test equipment.

Make sure that your test cables are good? Without that, good terminations are tested

as bad every time.

Make sure that your test equipment is fully charged and you have sparebattery

backup.

Documentation and Record Maintenance

It is very hard to troubleshoot cables when you don't know how long they are, where is the

route or how they were tested originally! So keep good records. It is recommended that the

following records be maintained and kept current on a daily basis:

schematic drawings to include "as-built" information for street maps records

splice loss data

end-to-end optical loss measurements

end-to-end OTDR signature traces

end-to-end power meter tests

definition of fibre optic

Documents