Page 11 - Photonics Essentials an introduction with experiments

Introduction

Introduction 5

physics of semiconductor devices, the design of biomedical instru-
mentation, optical fiber telecommunications, sensors, and micro
opto-electro mechanical systems (MOEMS). You may also want to
consider a summer internship as a test and measurement engineer
with one of the growing number of start-up companies in the opto-
electronics industry.
The largest market for photonic devices today is the telecommuni-
cations industry. Historically, this industry has been growing at
about 5% per year. The development of the optical fiber and the inter-
net have changed all that (see Fig. 1-1).
An optical fiber is generally a thin strand of glass that is used to
carry a beam of light. Once the light is introduced in the fiber, by us-
ing a lens, for example, it can only escape by propagating to the other
end of the fiber. The light beam is prevented from leaking out of the
sidewalls by an effect called total internal reflection. Thus, the fiber
acts as a guide for photons. When engineers showed that sending
high-speed communications by light waves was far superior to send-
ing communications by electricity, growth rates in the industry

10 14 OPTICAL { Multi-channel

(WDM)
Relative Information Capacity (bit/s) 10 8 6 4 SYSTEMS microwave systems
12
10
FIBER
10
Single channel
(ETDM)
10
Communication
10
Satellites
Advanced
10
coaxial and
{
2
10
Early coaxial cable links
Carrier Telephony first used 12 voice
0
channels on one wire pair
10
Telephone lines first constructed
10 –2
1880 1900 1920 1940 1960 1980 2000 2020 2040
Year
Figure 1.1. The growth of telecommunications systems got a big jolt with the deployment
of optical fibers in 1980, creating the first optical fiber telecommunications networks. There
was another big jolt in 1990 when optical amplifiers were rediscovered and adapted to op-
tical fiber telecommunications. This implemented multiple wavelength transmission (wave-
length-division multiplexing) and made it possible for the Internet to grow.

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