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How do fiber-optic cables transmit information using light?
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light
When white light is spread apart by a prism or a diffraction grating, the colours of the visible spectrum appear. The colours vary according to their wavelengths. Violet has the highest frequencies and shortest wavelengths, and red has the lowest frequencies and the longest wavelengths.
Fiber-optic cables transmit information by converting electrical signals into pulses of light, which are then sent through thin strands of glass or plastic.12
The process relies on the following components and principles:
- Conversion: An electro-optical transmitter, typically using light-emitting diodes or semiconductor lasers, converts digital or analog data into modulated light beams, usually in the infrared spectrum.13
- Transmission: The light travels through the fiber's core. The fiber is designed with an outer layer called cladding, which has a lower index of refraction than the core. This difference allows the light to remain trapped within the core through a phenomenon known as total internal reflection, enabling the signal to propagate over great distances with minimal loss of intensity.41
- Reception: At the destination, an optoelectronic receiver detects the light pulses and converts them back into electrical signals.3
This method is highly efficient, offering high bandwidth and immunity to electromagnetic interference compared to traditional copper wiring.243