How Are Optical Fibres Different From Ordinary Cables?

Answer 1:

Optical fibres, are used to transmit/receive light signals. In an optical fibre the light signal undergoes total internal reflection. The light hits the fibres at the glancing angle and is transmitted forward.

They have different layers of glass protected in layers ofbuffers,namely, hard buffer, soft buffer, core glass, and cladding glass The cladding glass has a low refractive index toward the core glass. When total internal reflection occurs the signal is transmitted. The soft and the hard buffer are protective coating which provide the necessary protection to the inner glass from external environments.

These optical fibres are more useful than copper because in copper, the wire is covered with a plastic covering and prone to electric sparks.In optical fibres the transmission and the reception takes place in different fibres as the receiver has to aligned properly to the transmitter. But in recent times, duplex method of transreceiving is in use.

In case of copper wire duplex transmission is well established. Optical fibres are also made from plastic if the application calls for economic rates and lower band width.

Answer 2:

The difference between a fibre optic communication system and other types of communication is that signals are transmitted as light in optic communication. Conventional electronic communication relies on electrons passing through wires. Since fibres transmit signals as light rather than current (as in other cables), they are immune to electromagnetic interference which causes noisy data transmission in wires. Because of this, they are used where data security is critical.

As no shielding is required against electromagnetic interference, they are smaller and more flexible, which makes installation much easier than metal cables.Fibre optic cable is more efficient than other cables as it has lower attenuation, mainly because light is not radiated out in the way that electricity is radiated from copper cables.

Non-conductive nature of fibres avoid spark hazards and damage to electronic equipment from power surges.They can transmit signals at higher speeds or over long distances.Copper wires are adequate for the vast bulk of computer data transmission over point to point links and local area networks. They react differently to tension as they are elastic and copper is inelastic. Optical fibres can be used to sense, illuminate, deliver laser power, display and image as well as to communicate. One disadvantage is that they are more expensive than other cables.

Published in The Hindu on May 23, 2002.