An optical fiber is a very thin strand of glass or plastic that can transmit light over long distances. You can imagine an optical fiber as a tiny, transparent tube through which light is “trapped” and can travel with nearly no loss.
In our everyday world, optical fibers are mainly used for high-speed internet, telephony, and data transmission. Unlike copper cables, optical fibers can transport data much faster and over greater distances. The light signal can carry billions of pieces of information at the same time, enabling very high speeds.
Optical fibers also play a very special role in quantum physics because they can transport photons – and photons are often used as carriers of quantum information.
Some important applications:
- Quantum communication: Optical fibers enable (entangled) photons to be sent over long distances. This theoretically allows for the establishment of tap-proof communication connections, as every measurement of a quantum state immediately changes the information.
- Quantum cryptography: In quantum key distribution (QKD) protocols, information is encoded in individual photons. Optical fibers reliably transport these photons between the sender and receiver.
- Quantum computer networks: Optical fibers can connect different quantum computers or quantum memories, allowing quantum information to be exchanged between remote systems.