Introduction to fiber optics

Contents......Page 5
Preface......Page 7
1 Optic fiber and light - a brilliant combination......Page 9
Light guiding......Page 10
Communications......Page 14
Terminology......Page 15
Refraction......Page 17
Units......Page 18
Media interface connector (MIC), fixed shroud duplex (FSD) or fiber data distributive interface ( FDDI) Û Figure 12.10......Page 0
Critical angle......Page 21
Total internal reflection......Page 22
Electromagnetic waves......Page 25
Electromagnetic spectrum......Page 26
Windows......Page 27
4 Propagation of light along the fiber......Page 30
Three points which are important to appreciate:......Page 34
Numerical aperture (NA)......Page 37
A couple of calculator notes......Page 38
What happens to the light which approaches the fiber outside of the cone of acceptance?......Page 39
Names given to different rays......Page 43
The decibel is a Iogarithnic unit......Page 47
Use of decibels in fiber optic circuits......Page 48
Decibels in a real circuit - what is the output power of the circuit shown in Figure 5.3?......Page 50
Using a decibel as a power level......Page 52
Example: Converting dBm to a power level......Page 53
Decibels used in a system design......Page 54
Power loss on an optic fiber......Page 55
6 Losses in optic fibers......Page 58
Fresnel reflection......Page 59
Bending losses......Page 61
Making use of bending losses......Page 63
Microbends......Page 64
Dispersion......Page 67
The effect on the data......Page 68
Modes......Page 69
Graded index fiber......Page 70
Intramodal (or chromatic) dispersion......Page 72
8 Real cables......Page 76
Basic choice of cable design......Page 77
Hybrid cable......Page 79
Cable design - other factors that may need considering......Page 80
Blown fiber......Page 85
The manufacture of optic fiber......Page 86
Advantages of optic fibers......Page 88
9 Connecting optic fibers - the problems......Page 90
Gap loss - Figure 9.3......Page 92
Alignment problems - Figure 9.4......Page 93
Connecting optic fibers - the preparation......Page 94
Cleaving......Page 96
Plastic fiber......Page 98
Preparation of the fiber......Page 100
Protecting the fiber......Page 101
Observing the alignment......Page 103
Automatic positioning......Page 104
Fusion splicing of the fibers......Page 106
Practical summary - how to do it......Page 109
Advantages and disadvantages......Page 111
How they work......Page 112
Specifications......Page 113
A practical guide to fitting a typical mechanical splice......Page 114
12 Connectors......Page 116
Connector parameters......Page 117
SMA (sub-miniature assembly - Figure 12.1)......Page 118
The two versions, 905 and 906 (now obsolete)......Page 119
Polishing styles - Figure 12.5......Page 120
Biconic connector......Page 122
Subscriber connector (SC)......Page 123
Adapters......Page 124
Terminating a silica glass optic fiber (fitting the connector)......Page 125
Fitting a connector on a silica fiber......Page 126
Some alternatives......Page 130
Final inspection......Page 131
Splitting ratio or coupling ratio......Page 134
Losses......Page 136
The tee-coupler - Figure 13.7......Page 139
Power levels in a tee network......Page 140
The star coupler......Page 142
Construction of couplers......Page 143
Variable coupler - Figure 13.15......Page 144
Lasers......Page 147
Laser safety......Page 149
Laser specifications......Page 150
PIN diodes......Page 152
Light receiver specifications......Page 153
Light source and power meter......Page 155
Calibration (or traceability)......Page 157
No dBr mode?......Page 158
The optical time domain reflectometer (OTDR)......Page 159
Inside the OTDR - Figure 15.10......Page 161
A simple measurement......Page 163
An OTDR display of a typical system......Page 165
Ghost echoes (false reflections)......Page 166
Effects of changing the pulsewidth......Page 167
Averaging......Page 170
Fault locator......Page 171
Optical power budget or loss budget or flux budget......Page 174
The usable bandwidth of optic fiber......Page 181
Analog transmission......Page 191
Converting an information signal into a digital form ( digitizing)......Page 192
Pulse code modulation (PCM)......Page 194
Biphase (Manchester) code......Page 195
How to get more digital signals on a single fiber......Page 196
How to send data further......Page 198
Copper cables......Page 200
Cable designs......Page 202
Making an entrance......Page 204
19 LANs and topology......Page 208
What bits of hardware are we likely to meet in a LAN?......Page 209
Topology at last......Page 210
Sitting in the stream......Page 214
Have you heard of BICSI?......Page 215
Contact addresses for BICSI......Page 217
Glossary......Page 218
Quiz time 2......Page 225
Quiz time 4......Page 226
Quiz time 5......Page 227
Quiz time 6......Page 228
Quiz time 7......Page 229
Quiz time 13......Page 230
Quiz time 16......Page 231
Quiz time 19......Page 233
Index......Page 235