Introduction:-
Optical Communication is a form of telecommunication that use light as the transmission medium.
It consists of a transmitter, which encodes a message into an optical signals, a channel, which carriers the signal it its destination, and a receiver , which reproduces the message from the received optical signal. In optical fiber communication optical fibers are use as the channel for the transmission of signals.
Classification:-
Optical fiber communication systems employ optical fibers as the transmission channel and use other optical communication supporting equipments at the transmitter and receiver end. Optical communication systems can be broadly classified into two categories. these are:
1)Analog Optical Fiber Communication System:-
The information source provides an electrical signal to the transmitter which consists of an electrical stage which drives an optical source to give modulation of the light wave carrier. The optical source which provides the electrical optical conversion may be a semiconductor laser or an ELD. The transmission medium consists of an optical fiber cable and the receiver is an optical detector which drives a further electrical stage and hence provides demodulation of the optical carrier. Photodiodes and in some instances photo transistors and photoconductors any be utilized for the detection of the optical signal and its conversion to electrical signal. Thus electrical interfacing at either end of the optical link is needed.
2.Digital optical fiber optical communication :-
The input signal from the information sources is suitably encoded for electrical optical transmission. The laser drive circuit directly modulates the intensity of the semiconductor laser with encoded digital signal. Hence a digital signal is lunched into the optical fiber cable. The Avalanche Photodiode detector is followed by a front end amplifier and equalizer or filter to provide gain as well as liner signal processing and noise bandwidth reduction. Finally , the signal obtained is decoded to give original digital information.
Besides this , optical communication systems can be classified as :
1.Guided optical communication systems.
2.Unguided optical communication systems.
In guided optical communication systems, the optical beam emitted by the transmitter remain spatially confined. However , in the case of unguided optical communication systems, the optical beam emitted by the transmitter spreads in space, similar to the spreading of microwaves.
Optical Communication is a form of telecommunication that use light as the transmission medium.
It consists of a transmitter, which encodes a message into an optical signals, a channel, which carriers the signal it its destination, and a receiver , which reproduces the message from the received optical signal. In optical fiber communication optical fibers are use as the channel for the transmission of signals.
Classification:-
Optical fiber communication systems employ optical fibers as the transmission channel and use other optical communication supporting equipments at the transmitter and receiver end. Optical communication systems can be broadly classified into two categories. these are:
1. Analog optical fiber optical communication systems.
2.Digital optical fiber optical communication systems.1)Analog Optical Fiber Communication System:-
The information source provides an electrical signal to the transmitter which consists of an electrical stage which drives an optical source to give modulation of the light wave carrier. The optical source which provides the electrical optical conversion may be a semiconductor laser or an ELD. The transmission medium consists of an optical fiber cable and the receiver is an optical detector which drives a further electrical stage and hence provides demodulation of the optical carrier. Photodiodes and in some instances photo transistors and photoconductors any be utilized for the detection of the optical signal and its conversion to electrical signal. Thus electrical interfacing at either end of the optical link is needed.
2.Digital optical fiber optical communication :-
The input signal from the information sources is suitably encoded for electrical optical transmission. The laser drive circuit directly modulates the intensity of the semiconductor laser with encoded digital signal. Hence a digital signal is lunched into the optical fiber cable. The Avalanche Photodiode detector is followed by a front end amplifier and equalizer or filter to provide gain as well as liner signal processing and noise bandwidth reduction. Finally , the signal obtained is decoded to give original digital information.
Besides this , optical communication systems can be classified as :
1.Guided optical communication systems.
2.Unguided optical communication systems.
In guided optical communication systems, the optical beam emitted by the transmitter remain spatially confined. However , in the case of unguided optical communication systems, the optical beam emitted by the transmitter spreads in space, similar to the spreading of microwaves.
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