OPTICAL FIBER IN COMMUNICATION SYSTEM
The most important application of optical fibers occurs in the field of communication.
Fiber optic communication systems comprise of the following units.
Information signal source:
The information signal to be transmitted may be voice, video or computer data (analog signals).
In order to communicate through optical fiber, the analog signals are converted into electrical signals.( by Analog to Digital converter)
The converted electrical signals are passed through the transmitter. Transmitter:
The transmitter is a modulator device used to receive electrical input signal, and then modulate it into digital pulses for propagation into an optical fiber.
The modulator consists of a driver and a light source as shown in fig.
The driver receives the electrical signals and then converts into the digital pulses.
These digital pulses are converted into optical signals after passing through a light source, generally either light emitting diodes (LED’s) or a semi conductor laser is used as light source.
The optical signals are then focused into the optical fiber as shown in fig.
Optical Fiber (or) Transmission medium:
The optical fiber is used as transmission medium between the transmitter and the receiver.
The optical signals are then fed into an optical fiber cable where they are transmitted over long distances using the principle of total internal reflection.
Receiver:
The receiver is a demodulator device used to receive the optical signals from the optical fiber and then convert into electrical signals.
The demodulator consists of a photodetector, an amplifier and a signal restorer.
The optical signals which are emerging from the optical fiber are received by photo
Detector.
The photodetector converts the optical signals into electrical signals.
The electrical signals are then amplified by the amplifier and the amplified electrical signals are converted into digital form.
The amplified electrical signals are fed to a signal restorer where the original voice is recovered.
Advantages of Optical Fibers in communication system:
High data transmission rates and bandwidth.
Low losses.
Small cable size and weight.
Immunity to EM radiations.
Safety due to lack of sparks.
Data security.
APPLICATIONS OF OPTICAL FIBERS:
(1) Due to high band-width, light can transmit at a higher rate up to 1014 to 1015 Hz. Than radio or micro-frequencies.
(2) Long distance signal transmission.
(3) They are used for exchange of information in cable television, space vehicles, sub-marines
(4) Optical fibers are used in industry in security alarm systems, process control & industrial automation.
(5) They are used in pressure sensors in biomedical & engine control applications.
This information is for knowledge only, not to hurt anyone's feelings.
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