Rami Arieli: "The Laser Adventure"

Rami Arieli: "The Laser Adventure" Chapter 9.4.7 page1

9.4.7 Optical Fiber Communications

Each channel in communications needs a bandwidth (range of frequencies around the central transmission frequency).

Optical frequencies (in the visible or Near-Infra-Red spectrum region) are very high frequencies (10¹⁴-10¹⁵ [Hz]).

The bandwidth of voice communication over phone lines is about 10 [kHz].

Thus, the number of phone conversations that can be send over optical communications system is measured in enormous numbers.

Diode lasers can be modulated at speeds of tens of Giga-Hertz (10¹⁰ [Hz]). and their light can be transmitted over tens of kilometers of optical fibers without the need for amplification.

Thus, Optical fiber communications provide the perfect solution for reliable high volume communication. This subject need its own Web site, so we shall just mention here a few facts.

Advantages of Optical Fibers:

Wide bandwidth.
Immunity from electrical interference.
Low weight.
Low cost.
More secure transmission.

Using optical fibers instead of the metal wires that transmit electrical signal have so many advantages, that all the new communication lines are made of optical fibers.

In one optical fiber to the home, all the communications need can be fulfilled:

Phone, television, radio, cable TV, computer communication, etc.