Optical Fibers

Optical fibers consist of thin strands of glass or glass like material which are so constructed that they carry light from a source at one end of the fiber to a detector at the other end. The light sources used are either light emitting diodes (LEDs) or laser diodes (LDs). The data to be transmitted is modulated onto the light beam using frequency modulation techniques. The signals can then be picked up at the receiving end and demodulated. The band width of the medium is potentially very high. For LEDs, this ranges between 20 and 150 mbps and higher rates are possible using LDs.
The major problems with optical fibers are associated with installation. They are quite fragile and may need special care to make them sufficiently robust for an office environment. Connecting either two fibers together or a light source to a fiber is a difficult process.
One of the major advantages of optical fibers over other media is their complete immunity to noise, because the information is travelling on a modulated light beam.
A side effect of this noise immunity is that optical fibers are virtually impossible to tap. In order to incept the signal, the fiber must be cut and a detector inserted.
Despite its shortcomings, optical fiber is an important technology and will be a very attractive transmission indeed.