Q.With a neat block diagram, explain the operation of a fiber optic communication system.

In a fibre optic system the information is first turned into digital light pulses, sent through the fibre as flashes of light, and then detected and converted back to the original signal at the receiver; the block diagram shows this transmit-and-receive path. …

[!TLDR]

Information → A/D → light source (LED) flashing ON/OFF → fibre optic cable → light detector → receiver circuitry → original information.

A fibre optic communication system carries information on a light beam. Its operation, shown in the block diagram, is as follows:

1. Input and digital conversion: The information signal — voice, video or computer data — is first converted into digital format using A/D converters that make it compatible with the medium.
2. Light source (transmitter): These digital pulses are used to flash a powerful light source ON and OFF very rapidly. In simple, low-cost, short-distance systems this light source is usually a LED that emits a low-intensity infra-red beam.
3. Transmission medium: The ON/OFF light-beam pulses are fed into a fiber optic cable (a glass or plastic light 'pipe') and transmitted over long distances with very low loss and immunity to electrical interference.
4. Detector (receiver): At the receiving end, a light-sensitive device (a photocell or light detector) detects the light pulses and converts the light back into an electrical signal.
5. Output: The receiver circuitry processes this electrical signal to recover the original information (voice, video or data). …