Fiber Optic Cabling

Fibre Optic Cabling

Second Edition

Barry Elliott

Mike Gilmore

Fiber Optic Cabling

OXFORD AUCKLAND BOSTON JOHANNESBURG MELBOURNE NEW DELHI

Newnes

An imprint of Butterworth-Heinemann

Linacre House, Jordan Hill, Oxford OX2 8DP

225 Wildwood Avenue, Woburn, MA 01801-2041

A division of Reed Educational and Professional Publishing Ltd

A member of the Reed Elsevier plc group

First published 1991

Second edition 2002

© Mike Gilmore and Barry Elliott 2002

All rights reserved. No part of this publication may be reproduced in

any material form (including photocopying or storing in any medium by

electronic means and whether or not transiently or incidentally to some

other use of this publication) without the written permission of the

copyright holder except in accordance with the provisions of the

Copyright, Designs and Patents Act 1988 or under the terms of a

licence issued by the Copyright Licensing Agency Ltd, 90 Tottenham

Court Road, London, England W1P 0LP. Applications for the copyright

holder’s written permission to reproduce any part of this publication

should be addressed to the publishers

British Library Cataloguing in Publication Data

A catalogue record for this book is available from the British Library

ISBN 0 7506 5013 3

Composition by Scribe Design, Gillingham, Kent, UK

Printed and bound in Great Britain

..........................................................Preface

............................................... Abbreviations

............................................ Safety statement

Cabling as an operating system .....................

1 Fiber optic communications and the

data cabling revolution................................ 1

Communications cabling and its role.............. 2

Fiber optics and the cabling market ............... 3

Fiber optic cabling as an operating system .... 7

The economics of fiber optic cabling .............. 9

2 Optical fiber theory ................................... 2

Basic fiber parameters ................................... 2

Refractive index.............................................. 12

Laws of reflection and refraction .................... 15

Optical fiber and total inter nal reflection ........ 18

Optical fiber constr uction and definitions....... 20

The ideal fiber................................................. 21

Light acceptance and numerical aper ture ..... 22

Light loss and attenuation .............................. 24

Intrinsic loss mechanisms .............................. 24

Modal distribution and fiber attenuation ......... 27

Extrinsic loss mechanisms ............................. 28

Impact of numerical aper ture on

attenuation...................................................... 31

Operational wavelength windows ................... 31

Bandwidth....................................................... 31

Step index and graded index fibers ................ 34

Modal conversion and its effect upon

bandwidth ....................................................... 36

Single mode transmission in optical fiber ....... 39

Bandwidth specifications for optical fiber ....... 45

System design, bandwidth utilization and

fiber geometries.............................................. 46

Optical fiber geometries ................................. 47

The new family of single mode fiber............... 48

Plastic optical fiber ......................................... 52

3 Optical fiber production techniques .......

.............................. Manufacturing techniques

Preform manufacture...................................... 55

Stepped index fiber preforms ......................... 55

All-silica fiber preforms ................................... 56

Fiber manufacture from preforms ................... 63

Fiber compatibility .......................................... 66

Clad silica fibers ............................................. 66

Plastic optical fiber ......................................... 67

Radiation hardness ........................................ 68

Primary coating processes ............................. 70

4 Optical fiber connection theory and

.......................................... basic techniques

................................... Connection techniques

Connection categories.................................... 73

Insertion loss .................................................. 73

Basic parametric mismatch ............................ 74

Fusion splice joints ......................................... 78

Mechanical alignment..................................... 79

Joint loss, fiber geometry and preparation ..... 84

Return loss ..................................................... 84

5 Practical aspects of connection

.................................................... technology

Alignment techniques within joints .................

The joint and its specification ......................... 90

Inser tion loss and component

specifications .................................................. 91

The introduction of optical fiber within joint

mechanisms ................................................... 95

Joint mechanisms: relative cladding

diameter alignment ......................................... 98

Joint mechanisms: absolute cladding

diameter alignment ......................................... 100

6 Connectors and joints, alternatives

........................................... and applications

Splice joints .................................................... 105

Demountable connectors ............................... 110

Standards and optical connectors .................. 121

Termination: the attachment of a fiber optic

connector to a cable ....................................... 124

Termination as an installation technique ........ 127

..................................... 7 Fiber optic cables

................................... Basic cabling elements

Cabling requirements and designs ................. 134

Fiber optic cable design definitions ................ 135

Inter-building (external) cables ....................... 138

Intra-building (internal) cables ........................ 141

Fiber optic cables and optomechanical

stresses .......................................................... 143

User-friendly cable designs ............................ 147

The economics of optical fiber cable

design............................................................. 147

8 Optical fiber highways ..............................

Optical fiber installations: definitions ..............

The optical fiber highway................................ 154

Optical fiber highway design .......................... 156

.....................................................

...........................................

9 Optical fiber highway design ...................

Nodal design .................................................. 168

Ser vice needs................................................ 172

Optical budget ................................................ 176

Bandwidth requirements................................. 185

Fiber geometry choices within the highway

design............................................................. 189

.................................. 10 Component choice

Fiber optic cable and cable assemblies .........

Connectors ..................................................... 199

Splice components ......................................... 200

Termination enclosures .................................. 201

11 Specification definition ..........................

................................. T echnical ground r ules

Operational requirement................................. 206

Design proposal ............................................. 211

Optical specification ....................................... 214

Contractual aspects of the specification

agreement ...................................................... 215

12 Acceptance test methods ......................

................................................... Fixed cables

Air-blown fiber testing..................................... 229

Cable assembly acceptance testing............... 229

Direct termination during installation and its

effect upon quality assurance......................... 239

Termination enclosures .................................. 239

Pre-installed cabling ....................................... 240

Short-range systems and test philosophies ... 240

................................ 13 Installation practice

Transmission equipment and the overall

contract requirement ...................................... 243

The role of the installer................................... 244

The typical installation .................................... 244

Contract management.................................... 245

Installation programme ................................... 248

Termination practices ..................................... 253

14 Final acceptance testing ........................

......................................... General inspection

Optical performance testing ........................... 259

Overall span attenuation measurement ......... 262

Optical time domain reflectometer testing

of installed spans............................................ 267

........................................ 15 Documentation

................................. Contract documentation

Technical documentation ............................... 275

The function of final highway

documentation................................................ 283

Internationalstandards concerning project

documentation................................................ 283

16 Repair and maintenance ........................

............................................................. Repair

Maintenance................................................... 289

............................................... 17 Case study

............................................ Preliminary ideas

.................................... Network requirements

Initial implementation for inter-building

cabling ............................................................ 292

Materials choice ............................................. 300

Bill of materials (fiber optic content) ............... 304

Installation planning........................................ 309

18 Future developments ..............................

................................................... Exotic lasers

New optical fibres ........................................... 311

Next generation components ......................... 312

New coding techniques .................................. 313

Appendix A Attenuation within optical

................................ fiber: its measurement

............................................................. Index

Mike Gilmore wrote the first edition of this book, the first major work

on practical data communications optical fibers, in 1991. Mike has since

become one of the most respected consultants in the field of

structured/premises cabling in Europe and is the UK national expert: it

thus falls on me to have the honour of being able to update this book

in 2001, after ten years of unparalleled and dramatic growth in the optical

communications industry.

In 2000, world production of optical fiber grew to 105 million kilo￾metres, itself a 300% growth over the second half of the last decade.

Optical fiber has become the undisputed medium of choice for long-haul

telecommunications systems and is even delivered direct to many larger

businesses. Trials are under way in Scandinavia and America to put fiber

into the home to judge the true economics of the competing broadband

technologies that will inevitably be delivered to every household.

The choice between different kinds of single mode fiber and the

network topology it sits within are business critical decisions for the

telecommunications network provider. The deregulation of the tele￾communications markets in most countries has led to an explosion of

growth in new carriers and an insatiable demand for optical fiber and

components such as wavelength division multiplexers.

This book, however, focuses upon the use of optical fiber in data

communications, local area networks and premises cabling. This is an area

traditionally seen as ‘lower-tech’ where lower-performance multimode

fiber was the order of the day. This was mostly true up until about 1997.

Before that, multimode fiber with an SC or ST connector on the end

would happily transport 100 Mb/s of data across a 2 kilometre campus.

Beyond 2 kilometres was the world of telecommunications.The advent of

gigabit Ethernet brought the ‘event horizon’ of single mode fiber down

to the 500 metre mark. The arrival of ten gigabit Ethernet brings single

mode all the way down to below 300 metres. At ten gigabit speeds the

worlds of data communications and telecommunications are merging.With

Preface

a new generation of Small Form Factor optical connectors to consider as

well as an unknown mix of multimode and single mode fibers, campus

optical cabling has suddenly got interesting again and nearly approaches

the pioneering spirit of 1991 where the use of optical fiber on a campus

was often seen as an act of faith, certainly in the choice of installer anyway.

One major change since 1991 has been the arrival of international

standards that define nearly every detail of component performance,

network design and system testing. The standards work is led by

ANSI/TIA/EIA in America, by CENELEC in Europe and ITU and

ISO/IEC for the rest of the world. All the appropriate standards are

referred to in this edition along with the performance, selection and

testing of all cables and components likely to be encountered in the LAN

cabling environment.

Fibre-to-the-desk has not met the promises of the early 1990s. Some

people say that copper cable has got better, with twisted-pair Category 5

and 6 copper cables offering frequency ranges up to 250 MHz. Copper

cable hasn’t changed that much; Shannon demonstrated mathematically the

information carrying capacity of communications channels, including

copper cables, in the 1930s.What has changed is the arrival of cheap digital

signal processing power that enables exotic coding schemes to fully exploit

the inherent bandwidth of well-made copper cables. Such microprocessors

would simply not have been available or affordable in the early 1990s.

Today, fiber-to-the-desk is the preserve of those organizations that really

need the extra benefits of optical fiber, such as longer transmission runs

(copper horizontal cabling is limited to 100 metres) and those who want

the security of optical fiber transmission, hence the popularity of fiber￾to-the-desk solutions within the military. Fibre tends to get cheaper, as do

the latest connectors and especially the optical transmission equipment,

which for too long has been a major barrier to the uptake of short-distance

optical fiber runs. Copper cable tends to get more expensive as the electri￾cal demands upon it get higher and higher, while other factors such as the

need to remotely power IP telephones over the cabling add yet more

ingredients to an already complex technical/economic argument.

In Mike Gilmore’s original book the last chapter was devoted to ‘future

developments’.All of his predictions have mostly come to pass and I finish

this edition with my predictions of the future. For a book written in 2001

it is perhaps appropriate to quote the great technical prophet, Arthur C.

Clarke, who wrote in 1975:

The only uncertainty, and a pretty harrowing one to the people who have

to make decisions, is how quickly coaxial cables are going to be replaced

by glass fibers, with their millionfold greater communications capability.

Barry Elliott

2001: Credo ut intelligam

xii Preface

ABF Air Blown Fibre

ANSI American National Standards Institute

APC Angled Physical Contact

ATM Asynchronous Transfer Mode

BER Bit Error Rate

CATV Community Antenna Television (cable TV)

CCI Core Cladding Interface

COA Centralized Optical Architecture

CPD Construction Products Directive

CWDM Coarse Wavelength Division Multiplexing

DFB Distributed Feedback (laser)

DMD Differential Modal Delay

DSF Dispersion Shifted Fibre

DWDM Dense Wavelength Division Multiplexing

dB decibel

EDFA Erbium Doped Fibre Amplifier

EF Encircled Flux

EIA Electronic Industries Alliance

EMB Effective Modal Bandwidth

EMC Electro Magnetic Compatibility

EMI Electro Magnetic Immunity (or sometimes ‘EM

Interference’)

ESD Electro Static Discharge

FCC Federal Communications Commission

FDDI Fibre Distributed Data Interface

FP Fabry Perot (laser)

FDM Frequency Division Multiplexing

FOCIS Fiber Optic Connector Intermateability Standard

GHz Gigahertz

GI Graded Index

Abbreviations

GPa Giga Pascal

HCS Hard Clad Silica

HPPI High Performance Parallel Interface

ICEA Insulated Cable Engineers Association

IEC International Electro Technical Commission

IEE Institute of Electrical Engineers (UK)

IEEE Institute of Electrical and Electronic Engineers (USA)

ISDN Integrated Services Digital Network

ISO International Standards Organization

ITU International Telecommunications Union

IVD Inside Vapour Deposition

LAN Local Area Network

LEAF Large Effective Area Fiber

LED Light Emitting Diode

LFH Low Fire Hazard

LSZH Low Smoke Zero Halogen

MAN Metropolitan Area Network

Mb/s Megabits per second

MCVD Modified Chemical Vapour Deposition

MEMS Micro Eectro Mechanical Systems

MHz Megahertz

NA Numerical Aperture

nm Nanometres

NEC National Electrical Code (USA)

NEMA National Electrical Manufacturers Association (USA)

NRZ Non-Return to Zero

NTT Nippon Telephone and Telegraph

NZDS Non Zero Dispersion Shifted (fiber)

OFL Overfilled Launch

OVD Outside Vapour Deposition

PAM Pulse Amplitude Modulation

PC Physical Contact

PCOF Primary Coated Optical Fiber

PCS Plastic Clad Silica

PCVD Plasma Chemical Vapour Deposition

PMD Polarization Mode Dispersion

PMMA Poly Methyl Methcrylate

POF Plastic Optical Fiber

PTFE Poly Tetra Fluoro Ethylene

PTT Public Telephone and Telegraph (operator)

PVC Poly Vinyl Chloride

OCDMA Optical Code Division Multiple Access

RML Restricted Mode Launch

SAN Storage Area Network

xiv Abbreviations

SC Subscriber Connector

SCOF Secondary Coated Optical Fiber

SCSI Small Computer System Interface

SFF Small Form Factor (optical connectors)

SMA Sub Miniature Assembly

SMF Single Mode Fiber

SNR Signal to Noise Ratio

SoHo Small Office Home Office

SONET Synchronous Optical Network

SROFC Single Ruggedized Optical Fiber Cable

TDM Time Division Multiplexing

TIA Telecommunications Industry Association

TIR Total Internal Reflection

TO Telecommunications Outlet

TSB Telecommunications Systems Bulletin

UL Underwriters Laboratory

VAD Vapour Axial Deposition

VCSEL Vertical Cavity Surface Emitting Laser

WAN Wide Area Network

WDM Wavelength Division Multiplexing

WWDM Wide Wavelength Division Multiplexing

Abbreviations xv