a way to transmit quantum information to a remote location
- two entangled photons are sent each to two different devices .
- once photons have reached their destinations, the two devices communicate using the entangled photon communication protocol
- if the two photons of the same pair have both reached their destination, the photons are sent to the ouput of the devices.
optical fibers can transmit photons to about 100km. Statistical counts of recieved photon states can help decide which information was sent.
photons can also be sent though freepace, for instance from a satellite. The main limitation on distance is then set by the precision of the lens transmitting the photons.
a lot of photons are lost during their transmission however the system only ouputs the photons of which the entangled photon has reached the other device.