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Digital communications
Optical-fibre communications became commercially viable in the 1970s and innovation continues today. This free course, Digital communications, will illustrate how very high data rates can be transmitted over long distances through optical fibres. You will learn how these fibres are linked, examine the technology used and assess the future direction of this continually developing area of communication.
Course learning outcomes
After studying this course, you should be able to:
- convert between wavelengths and frequencies
- describe the main differences between lasers and LEDs as used as light sources for optical-fibre communications systems
- describe the difference between direct and external modulation of a laser
- describe the difference in structure and performance of step-index multimode, graded-index multimode and single-mode optical fibres
- draw up a power budget for an optical-fibre communication link and use it to estimate the maximum link distance.
First Published: 10/08/2012
Updated: 13/11/2018
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transmitted over long distances (tens of kilometers) without amplifiers or regenerators.
Optical fibre has completely superseded copper wires as the primary medium for cabled
transmission over long distances. As demand for capacity has risen, fibre is now being
used even in LANs and the access network. An understanding of optical-fibre
communications are therefore very important for anyone with an interest in digital
communications.