Optical communication

Optical communication transmits information by encoding it onto light and sending it through free space or a guiding medium such as an optical fiber.

Optical fiber: A flexible transparent strand that guides light by total internal reflection or related confinement effects. It confines light to a path, enabling low-loss communication over long distances.
Wavelength-division multiplexing: A technique that carries multiple independent channels simultaneously on different optical wavelengths. It multiplies fiber capacity by assigning separate data streams distinct colors of light.
Submarine communications cable: An undersea cable system that carries telecommunications signals between countries and continents. Optical fibers in these cables carry much of the world’s intercontinental data traffic.
Radio communication: The transmission of information using modulated radio-frequency electromagnetic waves. Radio can cross obstacles and serve mobile users, unlike many optical links requiring a clear path or fiber.
Total internal reflection: The complete reflection of light at a boundary when it travels from a higher- to a lower-index medium above the critical angle. This effect keeps light confined within many optical fibers.
Optical dispersion: The spreading of an optical pulse because its components travel at different speeds or along different paths. Pulse spreading can make neighboring bits overlap and limits link distance or data rate.
Fiber to the premises: A broadband access network that extends optical fiber to a home or business location. It brings high-capacity optical links from network infrastructure close to end users.
Electrical telecommunication: The transmission of information through electrical signals in conductors such as copper cables. Copper carries data electrically, while optical systems encode it in light.
Optical transmitter: A device that converts an information-bearing electrical signal into modulated light. It launches the encoded optical signal into the transmission path.
Optical loss: The reduction in optical power as light propagates through a medium or passes components. Accumulated loss sets how far a signal travels before amplification or regeneration.

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