UNRAVELLING FIBERS

AND FIBER TO THE HOME

Prepared By:Vanhishikha

Bhargava(0941631056)

CONTENTS

Introduction to fiber optics and its Evolution Basics of optical fiber Color coating Wavelength bands-Transmission windows Types of optical fibers Advantages and Disadvantages Applications Connectors Adapters Attenuators Losses in optical fiber Splitters and types Field assembly connectors Cables and types Splicing and types Wavelength Division Multiplexing and Types

INTRODUCTION

Communications systems that carry information through a guided fiber cable are called fiber optic systems.

Use of optical fibers to replace conventional transmission lines and microwave wave-guide in telecommunication systems.

Light is effectively the same as RF radiation but at a much higher frequency, theoretically the information-carrying capacity of a fiber is much greater than that of microwave radio systems.

As they are not electrically conductive, hence very suitable for use in areas where electrical isolation and interference are severe problems.

EVOLUTION OF FIBER

1880 – Alexander Graham Bell 1930 – Patents on tubing 1950 – Patent for two-layer glass wave-guide 1960 – Laser first used as light source 1965 – High loss of light discovered 1970s – Refining of manufacturing process 1980s – OF technology becomes backbone of

long distance telephone networks in NA.

OPTICAL FIBER

Optical fiber is made from thin strands of either glass or plastic

It has little mechanical strength, so it must be enclosed in a protective jacket

Often, two or more fibers are enclosed in the same cable for increased bandwidth and redundancy in case one of the fibers breaks

It is also easier to build a full-duplex system using two fibers, one for transmission in each direction

TOTAL INTERNAL REFLECTION

Optical fibers work on the principle of total internal reflection

With light, the refractive index is listed The angle of refraction at the interface

between two media is governed by Snell’s law:

REFRACTION

air

glass

normal

incident ray

angle of refraction

angle of incidence

refracted ray

NUMERICAL APERTURE

The angle of acceptance is twice that given by the numerical aperture

RAYLEIGH'S SCATTERING

Rayleigh scattering is the elastic scattering of light or other electromagnetic radiation by particles much smaller than the wavelength of the light.

It can occur when light travels through transparent solids and liquids, but is most prominently seen in gases.

FRESNEL’S REFLECTION

When light moves from a medium of a given refractive index n1 into a second medium with refractive index n2, both reflection and refraction of the light may occur.

The relationship between these angles is given by the law of reflection:

COLOR COATING

TUBE COLOR ABBREVIATION

1 BLUE BL

2 ORANGE OR

3 GREEN GR

4 BROWN BR

5 SLATE SL

6 WHITE WH

7 RED RD

8 BLACK BK

9 YELLOW YW

10 VIOLET VI

11 ROSE RS

12 AQUA AQ

WAVELENGTH BAND

Fiber optic system transmit using infrared light, invisible to human eye, because it goes further in the optical fiber at those wavelength.

TRANSMISSION WINDOW

Band Wavelength range Description

O- band 1260 nm- 1360 nm Original band

E- band 1360 nm- 1460 nm Extended band

S- band 1460nm- 1530 nm Short wavelength band

C- band 1530 nm- 1565 nm Conventional band

L- band 1565 nm- 1625 nm Long wavelength band

U- band 1625 nm- 1675 nm Ultra long wavelength band

FIBER COMPOSITION

Core – thin glass center of the fiber where light travels.

Cladding – outer optical material surrounding the core

Buffer Coating – plastic coating that protects the fiber.

TYPES OF OPTICAL FIBERS

OPTICAL FIBERS

MULTIMODE FIBERS

STEP INDEX

GRADED INDEX

OM1/OM2/OM3

SINGLEMODE FIBERS

STEP INDEX

SINGLE-MODE STEP-INDEX FIBER

Used to transmit one signal per fiber. Used in telephone and cable TV. They have small cores(9 microns in diameter) . Transmit infra-red light from laser.

MULTI-MODE STEP-INDEX FIBER

Used to transmit many signals per fiber. Used in computer networks. They have larger cores(62.5/50 microns in

diameter) Transmit infra-red light from LED.

MULTI-MODE GRADED-INDEX FIBER

Core diameter : 50/62.5 microns. Cladding size: 125-140 microns. Refractive index changes continuously. Low dispersion. Core refractive index is made to vary as a function of

the radial distance from the center of the fiber.

OM1/OM2/OM3

OM1: refer to the commonly used 62.5/125 multimode fiber.

OM2: refer to the commonly used 50/125 cable. Both OM1 and OM2 easily supports applications

ranging from Ethernet to gigabit Ethernet. OM3: Typically this fiber optic patch cable is with

50/125 multimode fiber, with aqua jacket. They support bandwidth up to 10GB upto 300

meters.

ADVANTAGES

Wide bandwidth Light weight and small size Immunity to electromagnetic interference Lack of EMI cross talk between channels Lack of sparking Compatibility with solid state sources Low cost No emission licenses

DISADVANTAGES

High investment cost Need for more expensive transmitters and

receivers Fragility Opaqueness Requires special skills

APPLICATIONS

Telecommunications Local Area Networks Cable TV CCTV Optical Fiber Sensors Video Surveillance Links

FIBER OPTIC CONNECTORS

Terminates the fibers Connects to other fibers or transmission equipment

FIBER CONNECTOR TYPE

E 2000

FSMA FDDI

MPO BICONICMT- RJLC

STFCSC

FERRULE POLISH

To avoid an air gap Ferrule is polished flat,

or Rounded (PC—

Physical Contact), or Angled (APC)

Reduces reflectance Cannot be mated

with the other polish types

ADAPTERS

SC ST MT- RJ

LC

FC

E 2000

FSMA

MPO

BICONIC

FDDI

ATTENUATORS

SC LC FC

ST E 2000

MPO

MT- RJ

ATTENUATORS

VARIABLE ATTENUATORS

Ideal for adjusting OEM systems in production and lab applications.

These attenuators also exhibit low back reflection and good temperature stability.

FIXED ATTENUATORS

Fixed attenuators can limit, or attenuate. The amount of light passing through to the exact level your project.Used in applications where a pre-determined amount of light loss is specified.Most commonly used for test and measurement, optical sensors, and telecommunications applications.

TYPES OF LOSSES

LOSSES

ATTENUATION

SCATTERING

ABSORPTION

DISPERSION

MODAL

CHROMATIC

POLARISATIO

N MODE

LOSS MECHANISM

DISPERSION

MODAL DISPERSION

Modal dispersion is a distortion mechanism occurring in multimode fibers and other waveguides, in which the signal is spread in time because the propagation velocity of the optical signal is not the same for all modes.

POLARIZATION MODE DISPERSION

A special case of modal dispersion is polarization mode dispersion (PMD), a fiber dispersion phenomena usually associated with single-mode fibers. PMD results when two modes that normally travel at the same speed due to fiber core geometric and stress symmetry, travel at different speeds due to random imperfections that break the symmetry

CHROMATIC DISPERSION

Dispersion is the phenomenon in which the phase velocity of a wave depends on its frequency.

Dispersion is sometimes called chromatic dispersion to emphasize its wavelength-dependent nature.

SPLITTERS

A splitter is a device used to split the cable signal if the signal must be sent to two or more devices.

Optical splitters are also known as couplers. They are base on the type of cable management product they will be using.

Performance specifications of the splitters are given by the ITU- T G671 standard.

TYPES OF SPLITTERS

FUSED BICONICAL TAPER

SPLITTERS

PLANAR LIGHTWAVE CIRCUITS

FUSED BICONICAL TAPER SPLITTER

These are also known as singlemode splitters..

Operating wavelength is 1310nm or1550nm and the passband is 80nm.

The coupling ratio can change from 1:99 to 50:50.

Low insertion loss. Low excess loss. High directivity. Low polarization related

loss. More channels.

PLANAR LIGHTWAVE CIRCUITS

These type of splitters are smaller in footprint.

They offer slightly better losses across their split ratios than FBTs

Low insertion loss. Low excess loss. High directivity. High stability.

FIELD ASSEMBLY CONNECTORS

Designed for simple and fast field termination of single fibers, without polishing or adhesives.

The heart of the Quick-SC fast connector is a pre-polished ferrule and a mechanical splice inside the connector body.

Compatible with conventional SC and LC connector.

Easy and fast assembly without special tool

Reliable assembly with Assembly Jig and Fiber Holder appended to connector kit

CABLES

Fiber optic "cable" refers to the complete assembly of fibers, strength members and jacket. Fiber optic cables come in lots of different types, depending on the number of fibers and how and where it will be installed. There are classified as :

Cables (armored) Cables (unarmored) Distribution cables Drop cables

Cables (armored)

Duplex armored

Zipcord

Zipcord(round)

Simplex armored

Cables (unarmored)

Duplex unarmored

Zipcord

Zipcord(round)

Simplex unarmored

Distribution cables

4-fiber 8-fiber 12-fiber

24-fiber

Drop cables

1-fiber 2-fiber 4-fiber1-fiber

(messenger wire)

2-fiber(messenge

r wire)

SPLICES

Splices are a permanent join of two fibers

Lower attenuation and reflectance than connectors Stronger and cheaper than connectors Easier to perform than connectorization Mass splicing does 12 fibers at a time, for ribbon

cables

SPLICER

FUSION SPLICING

Melts the fibers together to form a continuous fiber

Expensive machine Strongest and best join for singlemode fiber

May lower bandwidth of multimode fiber

MECHANICAL SPLICING

Mechanically aligns fibers Contains index-matching gel to transmit light Equipment cost is low Per-splice cost is high Quality of splice varies, but better than

connectors Fiber alignment can be tuned using a Visual Fault

Locator

COMPARISON

Mechanical splicing

Fusion splicing

Reflection losses(-45 db to -55 db)

No reflection losses

Insertion loss(0.2 db)

Very low insertion loss(0.1 db to .15 db)

cost – high Comparatively less

WAVELENGTH DIVISION MULTIPLEXING

Data from each TDM channel is loaded on one optical frequency (or wavelength, ) of a particular wavelength band

These wavelengths are then multiplexed onto one fiber with the help of WDM multiplexers

Other side of the network these wavelengths are demultiplexed by using either optical filters, gratings or WDM demultiplexer

DENSE WAVELENGTH DIVISION MULTIPLEXING

Can achieve high system capacity by multiplexing

more WDM channels, each with relatively low data rate

Consist of a WDM combined with an optical amplifier,

to allow multiple wavelengths on a single fiber and

also avoid individual regeneration equipment for each

wavelength by use of line amplifiers

COARSE WAVELENGTH DIVISION MULTIPLEXING

o The total CWDM optical span to somewhere near 60 km for a 2.5 Gbit/s signal.oCWDM is also being used in cable television networks, where different wavelengths are used for the downstream (1310 nm) and upstream (1550 nm) signals. o Signals are not spaced appropriately for amplification by EDFAs. o Passive CWDM is an implementation of CWDM that uses no electrical power and separates the wavelengths using band pass filters and prisms.

ANY QUESTIONS OR COMMENTS?

THANK YOU