Introduction to fiber optics

Contents......Page 6
Preface......Page 8
1 Optic fiber and light - a brilliant combination......Page 10
Light guiding......Page 11
Communications......Page 15
Terminology......Page 16
Refraction......Page 18
Units......Page 19
Media interface connector (MIC), fixed shroud duplex (FSD) or fiber data distributive interface ( FDDI) Û Figure 12.10......Page 0
Critical angle......Page 22
Total internal reflection......Page 23
Electromagnetic waves......Page 26
Electromagnetic spectrum......Page 27
Windows......Page 28
4 Propagation of light along the fiber......Page 31
Three points which are important to appreciate:......Page 35
Numerical aperture (NA)......Page 38
A couple of calculator notes......Page 39
What happens to the light which approaches the fiber outside of the cone of acceptance?......Page 40
Names given to different rays......Page 44
The decibel is a Iogarithnic unit......Page 48
Use of decibels in fiber optic circuits......Page 49
Decibels in a real circuit - what is the output power of the circuit shown in Figure 5.3?......Page 51
Using a decibel as a power level......Page 53
Example: Converting dBm to a power level......Page 54
Decibels used in a system design......Page 55
Power loss on an optic fiber......Page 56
6 Losses in optic fibers......Page 59
Fresnel reflection......Page 60
Bending losses......Page 62
Making use of bending losses......Page 64
Microbends......Page 65
Dispersion......Page 68
The effect on the data......Page 69
Modes......Page 70
Graded index fiber......Page 71
Intramodal (or chromatic) dispersion......Page 73
8 Real cables......Page 77
Basic choice of cable design......Page 78
Hybrid cable......Page 80
Cable design - other factors that may need considering......Page 81
Blown fiber......Page 86
The manufacture of optic fiber......Page 87
Advantages of optic fibers......Page 89
9 Connecting optic fibers - the problems......Page 91
Gap loss - Figure 9.3......Page 93
Alignment problems - Figure 9.4......Page 94
Connecting optic fibers - the preparation......Page 95
Cleaving......Page 97
Plastic fiber......Page 99
Preparation of the fiber......Page 101
Protecting the fiber......Page 102
Observing the alignment......Page 104
Automatic positioning......Page 105
Fusion splicing of the fibers......Page 107
Practical summary - how to do it......Page 110
Advantages and disadvantages......Page 112
How they work......Page 113
Specifications......Page 114
A practical guide to fitting a typical mechanical splice......Page 115
12 Connectors......Page 117
Connector parameters......Page 118
SMA (sub-miniature assembly - Figure 12.1)......Page 119
The two versions, 905 and 906 (now obsolete)......Page 120
Polishing styles - Figure 12.5......Page 121
Biconic connector......Page 123
Subscriber connector (SC)......Page 124
Adapters......Page 125
Terminating a silica glass optic fiber (fitting the connector)......Page 126
Fitting a connector on a silica fiber......Page 127
Some alternatives......Page 131
Final inspection......Page 132
Splitting ratio or coupling ratio......Page 135
Losses......Page 137
The tee-coupler - Figure 13.7......Page 140
Power levels in a tee network......Page 141
The star coupler......Page 143
Construction of couplers......Page 144
Variable coupler - Figure 13.15......Page 145
Lasers......Page 148
Laser safety......Page 150
Laser specifications......Page 151
PIN diodes......Page 153
Light receiver specifications......Page 154
Light source and power meter......Page 156
Calibration (or traceability)......Page 158
No dBr mode?......Page 159
The optical time domain reflectometer (OTDR)......Page 160
Inside the OTDR - Figure 15.10......Page 162
A simple measurement......Page 164
An OTDR display of a typical system......Page 166
Ghost echoes (false reflections)......Page 167
Effects of changing the pulsewidth......Page 168
Averaging......Page 171
Fault locator......Page 172
Optical power budget or loss budget or flux budget......Page 175
The usable bandwidth of optic fiber......Page 182
Analog transmission......Page 192
Converting an information signal into a digital form ( digitizing)......Page 193
Pulse code modulation (PCM)......Page 195
Biphase (Manchester) code......Page 196
How to get more digital signals on a single fiber......Page 197
How to send data further......Page 199
Copper cables......Page 201
Cable designs......Page 203
Making an entrance......Page 205
19 LANs and topology......Page 209
What bits of hardware are we likely to meet in a LAN?......Page 210
Topology at last......Page 211
Sitting in the stream......Page 215
Have you heard of BICSI?......Page 216
Contact addresses for BICSI......Page 218
Glossary......Page 219
Quiz time 2......Page 226
Quiz time 4......Page 227
Quiz time 5......Page 228
Quiz time 6......Page 229
Quiz time 7......Page 230
Quiz time 13......Page 231
Quiz time 16......Page 232
Quiz time 19......Page 234
Index......Page 236