Page 178 - Introduction to Information Optics

Chapter 3 Communication With Optics

Shizhuo Yin
THE PENNSYLVANIA STATE UNIVERSITY

Light has been used for communication for more than five thousand years. In
ancient times, information was transmitted by blocking or transmitting light.
In recent years, with the advent of optic fibers and corresponding components
such as semiconductor lasers and receivers, fiber-optic communication has
become the core technology for long haul broadband communications. In this
chapter, we briefly introduce the basic concepts of fiber-optic communications.

3.1. MOTIVATION OF FIBER-OPTIC COMMUNICATION

With the exponential growth in transmission bandwidth usage, in particular
(due to the rapid growth of Internet data traffic), there is a huge demand on
transmission bandwidth. Fiber-optic communication is the best candidate to
fulfill this broad bandwidth due to its following unique features:

1. Huge bandwidth due to extremely high carrier frequency
The light signal has a very high carrier frequency. For example, at the
infrared communication window, assuming that / = 1 500 nm, the correspond-
ing carrier frequency, /, is as high as

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