- Involves the transmission of information by light through long transparant fibers made from glass or plastic .
- A light source modulates ( a light emitting diode (LED) or laser turns on and off or varies in intensity ) in a manner that represents the electrical information input signal .
- The modulating light is coupled to an optical fiber that propagates the light
- An optical detector at the opposite end of the fiber receives the modulating light and converts it back electrical signal identical to the input signal .
- Light transmission technieques can be divided into three major categories
-analog to digital modulation -computer data transmission .
-digital modulation -computer data transmission .
-analog modulation -voice and video transmission .
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