Quantum Communication With Entangled Photons

Harald Weinfurter

Hiroki Takesue, Toshimori Honjo, K. Harada +1 more

Entanglement is expected to play a crucial role in the next-generation quantum communication systems. This paper reviews recent quantum communication experiments over optical fiber using 1.5-µm telecom-band entangled photon pairs. After describing the telecom-band entanglement sources based on spontaneous parametric processes, we review three quantum communication experiments using entangled photons: a long-distance entanglement distribution, an entanglement-based quantum key distribution, and an entanglement swapping.

Zhen-Sheng Yuan, Xiao‐Hui Bao, Chao‐Yang Lu +3 more

Stefania Sciara, Hao Yu, Mario Chemnitz +15 more

Time-entanglement is a promising resource for the implementation of quantum communications over standard fiber networks. In particular, photonic qudits can enhance the performance of quantum communication, including quantum key distribution, in terms of noise robustness, quantum information content, distance reach, as well as security and secret key rates. However, time-entangled photonic qudits are not ready yet to be fully exploited for quantum communications in fiber networks that are fully compatible with standard telecommunication architecture. Here, we demonstrate the implementation of telecommunication-compatible quantum communications based on picosecond-spaced time-entangled qudits. To this end, we make use of an integrated photonic chip comprising a cascade of programmable interferometers and a spiral waveguide. We use entangled qudits to implement high-speed quantum key distribution, chip-to-chip entanglement distribution, and quantum state propagation over 60 km of standard fiber. Our results show the potential of time-entangled qudits for high-speed quantum communications in telecommunication-compatible architecture.

Nan Zhao

A scheme of long-distance quantum communication system based on entangled photon pairs is presented,which utilize entanglement as its essential resource.This entanglement enables phenomena such as quantum teleportation and perfectly secure quantum communication.The quantum repeater extends the length of the entangled photon pairs with high fidelity,the entanglement of photons between sender and receiver is built by entanglement swapping and entanglement purification.The quantum information is transferred by the principle of quantum teleportation.Performance analysis results show that the throughput quantum communication system of increases greatly with higher probabilities with which entanglement is built between sender's photons and receiver's photons.The transmitting distance of the quantum signal was determined by the series of the quantum repeater nodes.

Matej Peranić, Martin Lončarić, Anton Radman +1 more