Optical Fiber Communication An Introduction

Slides:



Advertisements
Similar presentations
Fiber Optics Technology
Advertisements

Chapter Twenty-Four: Fiber Optics
Instructor: Sam Nanavaty Fiber Optics-1. Instructor: Sam Nanavaty Advantages of Fiber Optics Bandwidth Low attenuation (few tenths of dB/Km) Immune to.
Transmisi Optik Pertemuan 10 Matakuliah: H0122 / Dasar Telekomunikasi Tahun: 2008.
S Digital Communication Systems Fiber-optic Communications - Supplementary.
Fiber Optics BASIC FIBER OPTIC LINK.
1 Lecture 5b Fiber-Optics in Digital Communication Systems & Electronic Interfaces 1. Introduction 2.Geometric Optics 3.Classification of Optical Fibers.
1 Part II: Data Transmission The basics of media, signals, bits, carriers, and modems Fall 2005 Qutaibah Malluhi Computer Science and Engineering Qatar.
Lecture 4b Fiber Optics Communication Link 1. Introduction 2
Fiber-Optic Communications
A Vocational Training from-. BATCH -4 (2013) TOPIC :- OPTICAL FIBRE CABLE.
Lecture Week 5 Satellite Communications Fibre Optic Communications
Fundamental of Fiber Optics. Optical Fiber Total Internal Reflection.
NET 535 : NEW TECHNOLOGIES DR.HANAA ABDALAZIZ ABDALLAH 1.
Fiber Optics Communications Lecture 11. Signal Degradation In Optical Fibers We will look at Loss and attenuation mechanism Distortion of optical signals.
By: Dr. N. Ioannides (Feb 2010)CT0004NI - L.06 – Fibre Optic Communications - pp 1/28 Fibre Optic Communications Saroj Regmi Lecture 06 CT0004NI Principles.
LIGHT COMMUNICATION. Fiber vs. Metallic Cables Advantages: Advantages: Larger bandwidthLarger bandwidth Immune to cross- talkImmune to cross- talk Immune.
1 Business Telecommunications Data and Computer Communications Chapter 4 Transmission Media.
FIBER PROPERTIES Transmission characteristics of a fiber depends on two important phenomena Attenuation Dispersion Attenuation or transmission loss Much.
 What is fiber-optic communication?  Method of transmitting information from one place to another  Sending pulses of light through optical fiber 
 Name : Amandeep Rai  Enrollment No. :  Department : Mechanical  Subject : Physics  Subject Teacher : Mitesh D.Parmar.
Dense Wavelength Division Multiplexing (DWDM) Technology
CS 453 Computer Networks Lecture 4 Layer 1 – Physical Layer.
Fiber Optics Communications Lecture 2. Introduction to Fiber Optic Communication System Communications refers to information transmission and reception.
Mahmoud Al-Saba – Majed Al-Bishi –
Objectives Understand the importance of fiber-optic technologies in the information society Identify the fundamental components of a fiber-optic cable.
Optical Fiber.
LOSSES IN FIBER OPTIC SYSTEM
Introduction to Network (c) Nouf Aljaffan
Optical Fiber Communications
Optical Fibre System By Mohd Nasir bin Said Telecommunications Department Advance Technology Training Centre Kulim Kedah Darul Aman.
Semester EEE440 Modern Communication Systems Optical Fibre Communication Systems En. Mohd Nazri Mahmud MPhil (Cambridge, UK) BEng (Essex, UK)
Propagation of Light Through Optical Fiber. Outline of Talk Acceptance angle Numerical aperture Dispersion Attenuation.
Fiber Optics.
Unit-3 FUNDAMENTALS OF FIBER OPTIC COMMUNICATION.
Optical Fiber. A thin (2-125  m) flexible strand of glass or plastic  Light entering at one end travels confined within the fiber until it leaves it.
Module 3 Transmitting Light on a Fibre.  An optical fiber is a very thin strand of silica glass in geometry quite like a human hair.  In reality it.
Data Transmission Common media concepts. Data Transmission and Media.
Digital Hierarchies There are two hierarchical structures that exist for digital networks: 1. Plesiochronous Digital Hierarchies 2. Synchronous Digital.
William Stallings Data and Computer Communications
Optical Emitters and Receivers
OPTICAL FIBER COMMUNICATION
Physical Transmission
Optical Fiber Basics Part-3
Fiber optic.
OPTICAL FIBER COMMUNICATION
OPTICAL FIBRE IN COMMUNICATION
Physical Transmission
by: Mrs. Aboli N. Moharil Assistant Professor, EXTC dept.
Physical Transmission
Physical Transmission
William Stallings Data and Computer Communications 7th Edition
OPTICAL SOURCE : Light Emitting Diodes (LEDs)
OPTICAL FIBERS
INTRODUCTION TO OPTICAL COMMUNICATION TECHNOLOGY
Optical Fiber.
OPTICAL FIBER COMMUNICATION
Physical Transmission
Dnyanasadhana college, Thane
Satish Pradhan Dnyanasadhana college, Thane
Transmission Media.
Lecture 11 – Application of Photonics
Introduction to Fiber Optics
ENGINEERING PHYSICS B.TECH :I YEAR SEM-I MECHANICAL & CIVIL
Physical Transmission
Computer Networks Topics: Twisted Pair and Fiber Optic Cable
Fiber Optic Transmission
William Stallings Data and Computer Communications
Fibre Optic Transmission
William Stallings Data and Computer Communications
Presentation transcript:

Optical Fiber Communication An Introduction

Optical Fiber Communication system with light as the carrier and fiber as communication medium Propagation of light in atmosphere impractical: water vapor, oxygen, particles. Optical fiber is used, glass or plastic, to contain and guide light waves Capacity Microwave at 10 GHz with 10% utilization ratio: 1 GHz BW Light at 100 Tera Hz (1014 ) with 10% utilization ratio:100 THz (10,000GHz)

History 1880 Alexander G. Bell, Photo phone, transmit sound waves over beam of light 1930: TV image through uncoated fiber cables. Few years later image through a single glass fiber 1951: Flexible fiberscope: Medical applications 1956:The term “fiber optics” used for the first time 1958: Paper on Laser

History Cont’d 1960: Laser invented 1967: New Communications medium: cladded fiber 1960s: Extremely lossy fiber: more than 1000 dB /km 1970: Fiber with loss of less than 2 dB/km 70s & 80s : High quality sources and detectors, SM fibres with Loss of <0.16dB/km 1988 : Optical Amplifiers Early 2000: High Speed transmission & large bandwidth

Increase in Bitrate-Distance product

Progress In Lightwave Communication Technology

Optical Fiber: Advantages Capacity: much wider bandwidth (10 GHz) Crosstalk immunity Immunity to static interference Safety: Fiber is non-metallic Longer lasting (unproven) Security: tapping is difficult Economics: Fewer repeaters

Higher initial cost in installation Interfacing cost Disadvantages Higher initial cost in installation Interfacing cost Strength: Lower tensile strength Remote electric power more expensive to repair/maintain Tools: Specialized and sophisticated

Optical Fiber Link Transmitter Input Signal Coder or Converter Light Source Source-to-Fiber Interface Fiber-optic Cable Output Fiber-to-light Interface Light Detector Amplifier/Shaper Decoder Receiver

Sources & Detectors Light source: LED or ILD (Injection Laser Diode): amount of light emitted is proportional to the drive current Source –to-fiber-coupler (similar to a lens): A mechanical interface to couple the light emitted by the source into the optical fiber Light detector: PIN (p-type-intrinsic-n-type) or APD (avalanche photo diode) both convert light energy into current

Plastic core and cladding Fiber Types Plastic core and cladding Glass core with plastic cladding PCS (Plastic-Clad Silicon) Glass core and glass cladding SCS: Silica-clad silica Under research: non silicate: Zinc-chloride: 1000 time as efficient as glass

Plastic Fiber Used for short run Higher attenuation, but easy to install Better withstand stress Less expensive 60% less weight

Types Of Optical Fiber Single-mode step-index Fiber Multimode step-index Fiber Multimode graded-index Fiber n1 core n2 cladding no air Variable n Light ray Index porfile

Single-mode step-index Fiber Advantages: Minimum dispersion: all rays take same path, same time to travel down the cable. A pulse can be reproduced at the receiver very accurately. Less attenuation, can run over longer distance without repeaters. Larger bandwidth and higher information rate Disadvantages: Difficult to couple light in and out of the tiny core Highly directive light source (laser) is required. Interfacing modules are more expensive

Multimode step-index Fibers: inexpensive; easy to couple light into Fiber result in higher signal distortion; lower TX rate Multimode graded-index Fiber: intermediate between the other two types of Fibers

Acceptance Cone & Numerical Aperture n2 cladding qC n1 core n2 cladding Acceptance angle, qc, is the maximum angle in which external light rays may strike the air/Fiber interface and still propagate down the Fiber with <10 dB loss. Numerical aperture: NA = sin qc = √(n12 - n22)

Losses In Optical Fiber Cables The predominant losses in optic Fibers are: Absorption losses: due to impurities in the Fiber material Material or Rayleigh scattering losses: due to microscopic irregularities in the Fiber Chromatic or wavelength dispersion: because of the use of a non-monochromatic source Radiation losses: caused by bends (micro or macro) in fiber Modal dispersion or pulse spreading: due to rays taking different paths down the Fiber Coupling losses: caused by misalignment & imperfect surface finishes

Absorption Losses In Optic Fiber 6 Rayleigh scattering & ultraviolet absorption 5 4 Loss (dB/km) 3 Peaks caused by OH- ions Infrared absorption 2 1 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Wavelength (mm)

Coupling Loses in Fiber Axial displacement Gap displacement Angular displacement Imperfect surface finish

Light Sources Light-Emitting Diodes (LED) Made from material such as AlGaAs or GaAsP Light is emitted when electrons and holes recombine Either surface emitting or edge emitting Injection Laser Diodes (ILD) Similar in construction as LED except ends are highly polished to reflect photons back & forth

ILD versus LED Advantages: Disadvantages: More focussed radiation pattern; smaller Fiber Much higher radiant power; longer span Faster ON, OFF time; higher bit rates possible Monochromatic light; reduces dispersion Disadvantages: Much more expensive Higher temperature; shorter lifespan

Light Detectors PIN Diodes Avalanche Photodiodes (APD) Photons are absorbed in the intrinsic layer Sufficient energy is added to generate carriers in the depletion layer for current to flow through the device Avalanche Photodiodes (APD) Photo-generated electrons are accelerated by relatively large reverse voltage and collide with other atoms to produce more free electrons Avalanche multiplication effect makes APD more sensitive but also more noisy than PIN diodes

Wavelength-Division Multiplexing WDM sends information through a single optical fiber using lights of different wavelengths simultaneously. Laser Optical sources l1 l2 ln ln-1 l3 Optical detectors Optical amplifier Multiplexer Demultiplexer

On WDM and D-WDM WDM is generally accomplished at 1550 nm. Each successive wavelength is spaced > 1.6 nm or 200 GHz for WDM. ITU adopted a spacing of 0.8 nm or 100 GHz separation at 1550 nm for dense-wave-division multiplexing (D-WDM). WDM couplers at the demultiplexer separate the optic signals according to their wavelength.

Progress In Lightwave Communication Technology

Lightwave Application Areas Optical interconnects Chip to Chip (Unlikely in near future) Board to Board (>1foot eg. CPU-Memory) Subsystem-Subsystem (Optics used Low Speed) Telecommunications Long Haul (Small Market-High Performance) LANs (Large Market Lower Performance)

The Internet

Global Undersea Fiber systems

Traffic Growth

Thanks!

Multiples Decimal Value Binary Value 1000 103 K kilo 1024 210 10002 106 M Mega 10242 220 10003 109 G Giga 10243 230 10004 1012 T Tera 10244 240 10005 1015 P Peta 10245 250 10006 1018 E Exa 10246 260 10007 1021 Z Zetta 10247 270 10008 Y Yotta 10248 280

Transmission Windows Band Description Wavelength Range O band Original 1260 to 1360 nm E band Extended 1360 to 1460 nm S band Short Wavelengths 1460 to 1530 nm C band Conventional (Erbium Window) 1530 to 1565 nm L band Long Wavelengths 1565 to 1625 nm U band Ultralong Wavelengths 1625 to 1675 nm