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Network IQ Training Manual Network IQ Training Manual

Network IQ Training Manual - PowerPoint Presentation

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Network IQ Training Manual - PPT Presentation

Chapter 1 Fibre Basics Fibre safety rules Keep all food and beverages out of the work area If fibre particles are ingested they can cause internal hemorrhaging Always ID: 560988

light fibre cable attenuation fibre light attenuation cable optical core power refraction dispersion index laser signal eye multimode bandwidth

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Slide1

Network IQ Training Manual

Chapter

1

– Fibre BasicsSlide2

Fibre safety

rules

Keep

all food and beverages out of the work area. If

fibre

particles are ingested

they

can

cause internal hemorrhaging.

Always

wear safety glasses with side shields to protect your eyes from

fibre

shards

or

splinters. Treat

fibre

optic splinters the same as you would treat glass splinters.

Keep

track of all

fibre

and cable scraps and dispose of them properly. If

available,

work

on black work mats and wear disposable lab aprons to minimize

fibre

particles

on

your clothing.

Fibre

particles on your clothing can later get into food, drinks

, and/or

be ingested by other means

.

Never look directly into the end of

fibre

cables – especially with a microscope – until

you are positive that there is no light source at the other end – having tested it with a power meter. Use a

fibre

optic power meter to make certain the

fibre

is

dark. When using an optical tracer or continuity checker, look at the

fibre

from an angle at least 6 inches away from your eye to determine if the visible light is present

.

Contact lens wearers must not handle their lenses until they have thoroughly washed their

hands and Do

not touch your eyes while working with

fibre

optic systems until your hands have

been thoroughly washed.

Keep

all combustible materials safely away from the curing ovens and fusion

splicers.

When finished with the lab, dispose of all scraps properly. Put all

fibre

scraps in a

properly marked container for disposal.

Thoroughly clean your work area when you are done.Slide3

Safety Precautions

Chemical Safety

Isopropyl Alcohol is Flammable at 12.2°C and can cause irritation to eyes on contact. In case of eye contact. flush eyes with water for at least 15 minutes

Laser Handling Precautions:

Communication System Laser Light is Invisible

Viewing it Directly does not Cause Pain. The Iris of the Eye will not Close Involuntarily as when Viewing a Bright Light. Consequently. Serious Damage to the Retina of the Eye is PossibleShould Accidental Eye Exposure to Laser Light be Suspected. Arrange for an Eye Examination Immediately

If any of Corning's procedural recommendations conflict with your company's safety procedures.

Then

your company's procedures should take precedence

.Slide4

Safety Precautions

Most sources are low-power and no great risk

High power sources might burn the retina with invisible light

Hea

l

thy

Co

r

nea

Damage

Retina DamageSlide5

New Classification of Lasers; IEC 60825

Class

Output description

Health/Safety Issues

Example Sources

Class 2

Emits 400-700nm (visible) light. < 1mW (Continuous)

Blink reaction normally prevents damage.

Many laser pointers.

Unicam CTS laser

Class 2M

Emits 400-700nm (visible) light

Blink reaction normally prevents damage. but can damage if viewed with optical magnifier

Rifle site. laser pointer

Class 3B

315 - 1400nm. <500mW (contin)

400-700nm. <30mJ (pulsed)

May damage eye if viewed directly or reflected light but not likely. Probability low to cause fire.

Industrial. military. medical lasers. Must have key switch and lock

Class 4

> 500mWCan burn skin and damage eye; may ignite materialsIndustrial. military. medical lasers. Must have key switch and lock

Lasers defined in terms of maximum permissible exposure (MPE)

Laser classification is a function of

power (pulsed or continuous)

beam coherence

wavelength

safety containment around beam

More details in reference slidesSlide6

Fibre Handling Precautions

Cleaved glass fibres are sharp and can pierce the skin easily.

Find all pieces of fibre so that they do not cause problems later.

Use tweezers to pick up pieces of the glass fibres and place them on a loop of tape or in a plastic bottle. Dispose of them properly.

Wear gloves when stripping cable.Slide7

Cable

Handling Precautions

Fibre optic cable is

sensitive to excessive pulling

.

bending and crushing forces. Do not bend cable more sharply than the minimum recommended

bend radius

.

Do not apply more

pulling

force to the cable than specified.Crushed. kinked or over-pulled cable.

may be damaged and require replacement of the cable.

Crack!

Rule of Thumb – Minimum Bend Radius

During Installation > 15 x Cable OD

Relaxed > 10 x Cable ODSlide8

Fibre versus Copper

Media

Unrepeatered

Distance

 

Bandwidth

Voice Channels

(per Cu pair or per fibre)

Typ. Cable Weight

Typ. Cable Diameter

Copper

2.5km

1.5

44

Mbps

(T-1)

24

5200kg/km

(400pair)

60mm(400pair)Fibre100+ km2.5 Gbps +(OC-48)32.000 + 130kg/km (24 fibre)11.6mm(24 fibre)

Fibre cables transmit more information over longer distance

Fibre

provides

1000

x

more

bandwidth

and up to 10

0

x

longer links

Fibre cables are smaller and lighter

Fibre cable with the same

information-carrying capacity (bandwidth) < 1% size. weight of equivalent copper cable Slide9

Fibre Anatomy

Core

:

Carries the light

Cladding

: Keeps the light in the coreCoating : protects the core & claddingCannot separate core from cladding!

125

μ

m

125

μ

m

50

μ

m

or

62.5μm8μmSingle-modeMultimodeSlide10

Fibre Anatomy

in

details

The Core:

is a thin filament made of glass or plastic, measured in

micra ( 1µm = 0,000001m) where the light pass through. The larger the diameter of the core, the more light it can conduct.Cladding: Layer that revests the core. Since it has a refraction index lower than the core, it prevents the light from being refracted, hence allowing the light to reach the reception device.Coating: Plastic layer that revest the skin, protecting the optical

fibre

from mechanical shocks and excess of bending.

Mechanic resistance

fibres

: Fibres

that help to protect the core against impacts and excessive tensions during their installation. They are usually made of a material called kevlar, the same used on bullet-proof vests.Outer Jacket: Is the jacket that covers the optical fibre

.Slide11

Types Of Optical Fibre

Single-mode:

Allows only one mode (ray) of light to travel

through the core

Multimode:

Allows multiple modes (rays) of light to travel

through the coreSlide12

Multimode vs. Singlemode – Total Internal Reflection

125

62.5

125

50

125

9

The physical properties of

singlemode

fibre

offer very low attenuation over distance, which is why

singlemode

fibre

is used to connect cities, campuses and wide area telephone and data networks. Multimode

fibre

cables experience more attenuation, or loss, per the same distance than

singlemode

fibre.Typically Multimode fibre is used within buildings and to connect buildings together in a campus environment. Lastly, plastic optical fibre has the highest attenuation, or loss of light per distance compared to the glass fibre cable types mentioned above. For many applications the maximum distance for plastic fibre cable is less than 10 meters.Slide13

Principle of Operation

-

Index of Refraction

Index of Refraction is abbreviated with the letter n

Speed of Light = 299.792.458 m/s (186.282 miles per sec)

Index of Refraction

1.0

1.0003

1.33

1.46

1.48

Medium

Vacuum

AirWater

CladdingCore

Speed of Light in a Medium

Speed of Light in a VacuumIndex of Refraction (n) =Slide14

Refraction

n

1

sin

1 = n2 sin 2

Refraction law

1

=

Angle

of

incidence2

= angle of refraction

refraction index n2

Interface

Medium 1

refraction

index n1 Medium 2 1 1 2 2 first wavefrontsecond wavefrontLot at the interfaceSlide15

Law of reflection

 = ´

Law of reflection

=

Angle

of

incedence

Interface

Medium 1

Medium 2

´

´

= Angle of reflectionIn most cases, refraction and reflection occur simultaneously: Only a portion of the light is reflected thereby and the remainder enters on the other medium (according to the law of refraction).index of refraction n1 index of refracton n2 Lot on the interfaceSlide16

Totalreflexion

Wenn n

1

> n

2

dann existiert ein Einfallswinkel G für den der Brechungswinkel = 90°sin G =n2/n

1

Für Einfallswinkel > 

G

tritt die

Totalrelfexion

auf Hinweise

:Soll nur text bleiben

, oder durch Drawings added

Text changedComments

added

G = Grenzwinkel

Grenzfläche

Medium 1 Medium 2 G ´G Brechungsindex n2 Brechungsindex n1

 > G

´ = 

Lot auf der Grenzfläche

Slide17

Wenn

θ

1

>

θ

G

Totalreflexion

Möwe erscheint hier

Wenn

θ

1

<

θ

G

Brechung

nLuft = 1.0003nWasser = 1.33sin θG = (nLuft/nWasser)  θG ≈ 49°θ ´

θ

2

Wirkungsprinzip

θ

G

θ

1

= Einfallswinkel

θ

G

= Grenzwinkel

θ

2

= Brechungswinkel

θ

´ = Ausfallswinkel

Fisch erscheint hier

θ

1

θ

1Slide18

Total Internal Reflection

If

(

n

core

>

n

cladding

) AND

If

critical angle not exceeded.

THEN Total Internal Reflection occurs

=

 Slide19

System Performance Parameters

Light sources transmit light through the

fibre

at various

wavelengths

As the light travels down the fibre. attenuation occursAs the light travels down the fibre

.

dispersion

occurs which affects

bandwidthSlide20

System Performance Parameters

WAVELENGTH

is a characteristic of

light that is emitted

from the light sourceand is measured innanometers (nm)

TYPICAL OPERATIONAL WAVELENGTHS

850 nm

(MM)

1300 nm

(MM)

1310 nm

(SM)

1550 nm(SM)Slide21

Attenuation - Definition

Attenuation is

measured in

decibels (dB)

decibel (dB) = -10 log (P

out

/P

in

).

Pout = Received Power P

in = Transmitted PowerSlide22

Attenuation Samples

Attenutation

in

Decible

Remaining

power in %0.197.70.295.50.3

93.3

0.4

91.2

0.5

89.10.6

87.70.785.10.883.2

0.981.1179.4 ≈ 80263.1

350.1 ≈ 50439.8531.66

25.1 ≈ 25719.9 ≈ 208

15.8912.61010.0201.0300.1

400.01Performance P in mWPerformance in dBm1 W+30

dBm100 mW+20 dBm10mW+10 dBm5 mW+7

dBm

1 mW

0 dBm500 µW-3 dBm100 µW-10 dBm50 µW-20 dBm10 µW-23 dBm1 µW-30 dBm100 nW-40 dBm10 nW-50 dBm1 nW-60 dBm100 pW-70 dBm10 p W-80 dBm1 pW-90 dBm in dBm = 10lg  Slide23

Types of Attenuation

Attenuation - measure of optical power loss.

T

wo Types of Attenuation:

1. Intrinsic 2. Extrinsic

- Absorption - Macrobending

- Scattering

- MicrobendingSlide24

Spectral Attenuation Curve

850

1300/1310

1550

“Windows of Operation”

MM

SM

Water

Peak

1383 nmSlide25

Intrinsic Attenuation – Absorption and Scattering

Absorption

- natural impurities in the

glass absorb light energy.

Scattering

- Light rays interact with glass on the atomic level and are scattered into new pathways that may be lost through the cladding.Slide26

Extrinsic Attenuation

Macrobending

Loss due to large scale bending from

ex

ternal sources

Corning’s new ClearCurve

®

fibres are macrobend resistant through innovative barriers between Core and Cladding

- Single-Mode ClearCurve

- Multimode ClearCurve

(see reference pages for details)Slide27

Extrinsic Attenuation

Microbending

loss due to small scale

distortions

S

mall bend affecting the fibre eg

.

cable ties installed too tight

.Slide28

System Performance Parameters: Dispersion

Dispersion is d

efined as the spreading of a light

pulse as it

travels down a fibre

Bandwidth is d

efined as the amount of information

that a

system can carry such that each pulse of light is

distinguishable by the

receiverSlide29

Dispersion - Modal Dispersion

In multimode fibre. an input pulse travels in different paths. called “modes”

Each ball is a mode

All of the balls start from the same pulse

Modal dispersion only occurs in MM fibreSlide30

Dispersion - Effect on Signal

Affects quality of the transmission

-Bandwidth

1 0 1

1 1 1

logical information

electrical input signal

transmitted optical signal

received optical signal (with dispersion)

electrical output signal

logical information

BIT ERRORSlide31

Optical transmitters

Beam Shape

Source Name

Light beam

Power/ Speed

Relative Cost

Light Bulb

Light not directed or focused. rays travel many directions

Low power (in 1 direction)

Cheap

LED

L

ight

E

mitting

D

iode

Large cone of light. large spectral width

Low power. Max speed 622Mbps

Cheap

LASER

L

ight

A

mplification by

S

timulated

E

mission of

R

adiation

Parallel beams. focused. very small spectral width

High power. very fast 10+Gbps

Expensive

VCSEL

V

ertical

C

avity

S

urface

E

mitting

L

aser

Well focused beam

. small spectral width

Mid power. very fast: 10Gbps

EconomicalSlide32

Optical transmitters - Spot size

The spot-size and the laser launch are factors which affect the fibre-bandwidth.

cladding/125µm

LASER

Tx

VCSEL

LED

Tx

Tx

core/50µm

coatings/250µm

Spot size 4-10µm

Spot size 20-30µm

Spot size > 100 µmSlide33

Pros and Cons Optical

Fibre

vs

Copper

Pros:High bandwidth: Using wavelength division multiplexing allows multiple 100 Tbit / s can be transmitted per fiberLow attenuation, high coverage: Without Optical Amplifier typical 100km, with optical amplifiers from several hundred to one thousand kilometersThe attenuation in the optical waveguide, as opposed to copper conductors independent of the frequency of the transmitted signalGlass is an insulator: Allows Isolation between transmitter and receiver.Immunity to electro-magnetic interferencesNo

signal radiation and thus relative

privacy

Use

in hazardous areas is possible

ConsOver fiber optic cabling no power supply is available. Requires additional copper cablingFiber

optic cable can not be located, if it contains no copper.High requirements in connection technology: Plug wiring, splicingMeasurement consumingThe components are still expensiveSlide34

Summary

Light signal travels in the core of the

fibre

.

This is possible because the cladding IOR is less than the core IOR

(ncore >ncladding)

The light rays travel in paths called modes.

Two types of

fibre

:

Multimode

Single-modeOptical signal loss (attenuation) is measured in dB (deciBel)Attenuation in

fibre caused by:Intrinsic Characteristics: Absorption. ScatteringExternal Characteristics: Macro/Micro- bendsAn optical pulse spreads as it travels through a fibre. Called Dispersion.

Sources/Transmitters used in Fibre SystemsLEDsVCSELsLasersSlide35