Principle of optical fibre communication

Optical Fibre Communication:

Optical fibre communication is a method of communication in which an optical wave passes through optical fibre by the total internal reflection principle. This optical signal consists of the electrical signal (Also known as information) and the laser beam i.e. a carrier wave. The optical fibre is used as a waveguide or transmission medium in optical fibre communication.

Principle of optical fibre communication:

In the optical fibre communication principle, the information (such as voice) is first converted into an electrical signal. Then it is modulated onto the laser beam (Also known as a carrier wave). In the modulation process, The electrical signal is superimposed onto the laser beam and the frequency of laser light changes with the frequency of the electrical signal. The optical fibre communication uses the pulse code modulation (PCM) for transmitting the optical signal. Now modulated optical signal passes through the optical fibre or waveguide, by the principle of total internal reflection, from the transmitter to the receiver.

The receiver receives the optical signal and demodulates it. In the demodulation process, the detector detects the signal and removes the carrier wave from the electrical signal. So the original information is received at the receiver end as sent by the transmitter.

Optical fibre communication follows the principle of total internal reflection. When the light is incident at a certain angle into the core of the optical fibre, total internal reflection occurs within the optical fibre causing long-distance transmission.

Light in the optical fibre can be classified into two types: meridional rays, which travel along the meridional plane, and oblique rays, which propagate at an angle to the fibre axis.