Book contents
- Frontmatter
- Contents
- List of figures
- List of tables
- Acknowledgements
- Introduction
- Part I The technology – how electronic devices work – digital systems and software
- Part II Innovators, entrepreneurs, and venture capitalists
- Part III Global reach, global repercussions
- Appendix 1.1 Smaller, faster, more efficient MOSFETs
- Appendix 1.2 Building multi-transistor logic gates
- Appendix 1.3 MOSFETs in memory devices
- Appendix 1.4 CMOS reduces logic gate power dissipation
- Appendix 1.5 Laser diode basics
- Appendix 1.6 Light-emitting diodes (LEDs)
- Appendix 1.7 Photodetectors
- Appendix 1.8 Making fiber optic cables
- Appendix 1.9 Principles of LCD displays
- Appendix 2.1 The demise of analog computers
- Appendix 2.2 IP, TCP, and the Internet
- Appendix 2.3 Building an object-oriented program
- Index
Appendix 1.8 - Making fiber optic cables
Published online by Cambridge University Press: 07 December 2009
- Frontmatter
- Contents
- List of figures
- List of tables
- Acknowledgements
- Introduction
- Part I The technology – how electronic devices work – digital systems and software
- Part II Innovators, entrepreneurs, and venture capitalists
- Part III Global reach, global repercussions
- Appendix 1.1 Smaller, faster, more efficient MOSFETs
- Appendix 1.2 Building multi-transistor logic gates
- Appendix 1.3 MOSFETs in memory devices
- Appendix 1.4 CMOS reduces logic gate power dissipation
- Appendix 1.5 Laser diode basics
- Appendix 1.6 Light-emitting diodes (LEDs)
- Appendix 1.7 Photodetectors
- Appendix 1.8 Making fiber optic cables
- Appendix 1.9 Principles of LCD displays
- Appendix 2.1 The demise of analog computers
- Appendix 2.2 IP, TCP, and the Internet
- Appendix 2.3 Building an object-oriented program
- Index
Summary
To gain an appreciation of how one builds optical fibers for different communications applications, look at Figure A-1.8.1, which illustrates three different types of fibers.
Each of these types is distinguished by its refractive index profile. The refractive index profile is a key part of fiber design because it determines the product's ability to propagate short pulses and maintain their shapes over long distances.
The topmost illustration shows the simplest stepped-index profile fiber (also called multimode). This is the least costly type to manufacture, but it has the poorest pulse propagation characteristics. It is used for transmission over short distances.
Single mode fiber with a tailored stepped refractive index profile, shown in the second illustration, is much better at keeping the pulse shape intact, but it is costlier. This type of fiber is used for high-data-rate communications over long distances.
Finally, in the illustration at the bottom of the figure, we have a multimode, graded-index fiber that falls between the two profiles above it. This fiber has applications in intermediate distance transmission.
In all three examples the glass fibers are encased in claddings. Large numbers of individual cladded fibers are enclosed in cables that protect them from external forces and the elements. Special techniques exist for creating cables that can survive undersea deployment and other demanding environments.
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- Competing for the FutureHow Digital Innovations are Changing the World, pp. 372 - 373Publisher: Cambridge University PressPrint publication year: 2007