Optical Fiber - PowerPoint Presentation

Slide1

Optical FiberAUTO3160 - Optics and SpectroscopySpring 2012

Miguel Angel Chourio

Master’s degree in Telecommunication Engineering

University of Vaasa, Finland Slide2

What is a Optical Fiber Single Mode Optical

Fiber Multimode Optical Fiber

Single

mode Vs. Multimode FiberSnew’s Law - Total Internal ReflectionHow is glass optical Fiber made ApplicationsConclusionsReferences

INDEXSlide3

Optical FiberOptical Fiber uses glass to guide the light impulses from source to destination. Optical Fiber provides a very large bandwidth data rates.Based on its requirements and needs, Networks communication are implemented as

Copper Optical Fiber Wireless (Signal are propagated over the

air)Slide4

Glass Fiber Structure The core vary

its dimensions either the fiber is

single

or multimode. Light enter into the core and its cladding

along the fiber

The

Cladding

surronds

or

cover

the

core

and

is

designed

to

prevent

light

loss

from

the

fiber

.

Since

the

light can

only

travel

in

one

direction

over

the

optical

cable,

two

fibers

are

required

to

support

full

duplex

operations

Slide5

Ray Light explanationTypically, the core size on Multiple Fiber are large enough so that, multiple light ray can enter to the core at

different angles along the fiber. Multimode fiber employ Light Emitting Diodes (LEDs) with its proper angles to represent the transmitted data as bits along the media. Due the light enters the fiber at different angles, it takes different amount of time to travel down the fiber, and it may become confuse at the receiver side.

This effect known as

modal dispersion, limit the length of multimode fiber segments. Slide6

Ray Light explanationIn “Single Fiber”, the core

is so tiny that only one light ray

which is perpendicular to the cable may be propagate along. Single Fiber employs a single Ray of Light as source generator to propagate the signals, because the laser is uni-directional and travels

along the center of

the

fiber

. Slide7

Single mode vs. Multimode Fibers

Single-

Mode

MultimodeSmall core Less dispersion Carry a single ray of light, usually generated from a laser.

Employ for

long

distance

applications

(100Km)

Uses as

Backbone

and

distances

of

several

thousands

meters

.

Larger

core

than

single

mode

cable.

Allows

greater

dispersion

and

therefore

,

loss

of

signal

.

Used

for

shorter

distance

application

,

but

shorter

than

single-

mode

(up

to

2Km)

It

uses LED

source

that

generates

differtes

angles

along

cable.

Often

uses in

LANs

or

small

distances

such

as campus

networks

. Slide8

Waveguide calculation of Fiber Mode

Here is fiber mode calculation based on Waveguide Calculation by Fiber Optics for Sale Company (USA)V number determines the numbers of guided modes.

When

V number is smaller than 2.405 only one mode can be guided by the fiber,

this is called

single

mode

fiber

.

When

V

Numer

is

larger

than

2.405

severals

modes

can be

guided

by

the

fiber

.

As

higer

V

number

as

larger

number

of

modes

,

this

is

called

Multimode

FiberSlide9

Multimode

Fibers is more complex

The multimode fiber keeps the same structure as single mode unlike the sieze of the core glass is bigger.

Refractive

index

profile

in

multimode

fibers

The

x (

axes

)shows

fiber

raduis

The

y (

axes

) shows

refractive

index

The

core

usually

has a

refractive

index

n1 = 1.48

The

cladding

has a

refractive

index

n2 = 1.06

This

is

called

Step-index

fiberSlide10

Snew’s Law - Total Internal Reflection

Snew’s Law describe the relation between the

angles

of incidents and refractions. When the Light Ray pass from a higher index material to a lower index material, light refraction occurs. When light incidents at interface between the core and the cladding has differents angles

some power are reflacting

back and

some

power

enter

into

the

cladding

As

the

angle

is

increases

larger

than

the

target no more light

enter

into

the Cladding layer and all the light reflect back into the core. This is called “Total Internal Reflection”.

Core

CladdingSlide11

Optical

Fiber manufacturer

Generally

it consists on 2 steps by Glass Fiber preform

Fiber

Manufacturing

Process

1st

Step

a

preform

is

made

and

it

has quite

exactly

the

same

proportion

core

as

the

cladding material.2nd Step the

preform

pass

through a monitor to deploy the final fiber into a drum to be storage and distributed. Slide12

Special fiber drawing towerOptical

Implementation Technology offers by Yangtze Optical Fibre and Cable Company Ltd. (YOFC) a Chinese company established in May 1988.

Reference

http://en.yofc.com.cn/jjfa/&FrontComContent_list01-1293619915029ContId=279b108f-7f52-4951-a347-9afb3bec0dcb&comContentId=279b108f-7f52-4951-a347-9afb3bec0dcb&comp_stats=comp-FrontComContent_list01-1293619915029.htmlSlide13

Nowadays, Optical Fibers connects the world under the sea and over the land

Basically all digital communications travels via fiber.

A single fiber can carry more communications than the biggest copper cable.

Optical Fibers ApplicationsSlide14

Optical Fibers ApplicationsTelecommunications | Internet | Fiber at Home Video Streaming | Data Centers | Computer Networks Video and Audio Military | Governments | Airports |HospitalIntelligent | Public transportations

Everywhere Slide15

Conclusion Optical Fiber = Optical +

Fiber “ At Speed of Light”Single Mode Fiber provides higher

data

rates speed and more distance than Single ModeSingle Mode uses a single Ray of Light while Multimode Fiber employ Light Emitting Diodes (LEDs) to propagate the signal. At present, the fiber application might be infinite, however a deep analysis

and design is recommended

before

implement

a

network

. Slide16

Reference[1] Yangtze Optical Fibre and Cable Company Ltd. (YOFC) http://en.yofc.com.cn/jjfa/&FrontComContent_list01-1293619915029ContId=279b108f-7f52-4951-a347-9afb3bec0dcb&comContentId=279b108f-7f52-4951-a347-9afb3bec0dcb&comp_stats=comp-FrontComContent_list01-1293619915029.html

[2] CISCO Networking Academy Program CCNA 1 and 2 book, 3rd Edition, Indianapolis – CISCO press, 2003.

[3] About Optical

Fiber, link: http://en.wikipedia.org/wiki/Optical_fiber[4] Eugene Hecht – Optics , International Edition, Pearson Education Slide17

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