Photonics essentials: an introduction with experiments

284 Pages·2002·6.921 MB·English

by  Thomas P. Pearsall

Source: Photonics Essentials
Part
I
Introductory Concepts
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Introductory Concepts
Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com)
Copyright © 2004 The McGraw-Hill Companies. All rights reserved.
Any use is subject to the Terms of Use as given at the website.
Source: Photonics Essentials
Chapter
1
Introduction
Photons have been around ever since the Big Bang, which is a long
time. Photons, by definition, are always on the move: 3 × 1010 cm/sec
in air. Some of the important milestones in the history of the human
civilization are those at which we have improved our ability to control
the movement of photons. A few notable examples are the control of
fire, the design of lenses, the conception of Maxwell’s equations, the
invention of photography, broadcast radio, and the laser.
Photonics is the study of how photons and electronics interact, how
electrical current can be used to create photons as in a semiconductor
laser diode, and how photons can create an electrical current, as in a
solar cell. The field of photonics is in its infancy. Great discoveries re-
main to be made in using photonics to improve our lives.
The list of applications in photonics is long. Some of the rapidly
growing areas are:
Ecology:
Solar cell energy generation
Air quality and pollution monitoring
Imaging:
Camcorders
Satellite weather pictures
Digital cameras
Night vision
Military surveillance
3
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Introduction
4 Introductory Concepts
Information displays:
Computer terminals
Traffic signals
Operating displays in automobiles and appliances
Information storage:
CD-ROM
DVD
Life Sciences:
Identification of molecules and proteins
Lighting
Medicine:
Minimally invasive diagnostics
Photodynamic chemotherapy
Telecommunications:
Lasers
Photodetectors
Light modulators
Telecommunications is an application of considerable activity and
economic importance because of the transformation of the world-wide
communications network from one that used to support only voice
traffic to one that now supports media transmitted through the Inter-
net, including voice, data, music, and video. Of course, in the digital
world these different media are all transmitted by ones and zeros.
However, if a picture can be said to be worth more than a thousand
words, a transmitted picture counts for about a million words. The
growth of the internet and its capacity to transmit both images and
sound has been made possible only because of the vast improvements
in speed and capacity of fiber optic telecommunications. At the heart
of this revolution are the semiconductor laser, fast light modulators,
photodiodes, and communications-grade optical fiber.
From this text you can learn what makes these key devices work
and how they perform. Laboratory measurements are emphasized for
an important reason: there are many different kinds of photonic de-
vices, but only a few basic characterization measurements. When you
learn these laboratory techniques, you can measure and understand
almost any kind of device. The experiments are based on components
that you can find easily in any electronics store. This means that the
laboratory fees should be reasonable, and that you can quickly find a
replacement device when you need one.
This course is an excellent preparation for subsequent work in the
Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com)
Copyright © 2004 The McGraw-Hill Companies. All rights reserved.
Any use is subject to the Terms of Use as given at the website.