Time-energy Entangled Photons Research Articles

Chirp and Compress: Toward Single-Cycle Biphotons

The Letter describes a technique for the spontaneous generation of chirped time-energy entangled photons. Transmitting either photon through an appropriate dispersive medium results in a temporally compressed, transform limited biphoton. At maximum bandwidth, the biphoton is a single cycle in length, with a waveform that has the same characteristic shape as a classical single-cycle pulse.

Long-distance Bell-type tests using energy-time entangled photons

Long-distance Bell-type experiments are presented. The different experimental challenges and their solutions in order to maintain the strong quantum correlations between energy-time entangled photons over more than 10 km are reported and the results analyzed from the point of view of tests of fundamental physics as well as from the more applied side of quantum communication, especially quantum key distribution. Tests using more than one analyzer on each side are also presented.

Pulsed Energy-Time Entangled Twin-Photon Source for Quantum Communication

A pulsed source of energy-time entangled photon pairs pumped by a standard laser diode is proposed and demonstrated. The basic states can be distinguished by their time of arrival. This greatly simplifies the realization of 2-photon quantum cryptography, Bell state analyzers, quantum teleportation, dense coding, entanglement swapping, GHZ-states sources, etc. Moreover the entanglement is well protected during photon propagation in telecom optical fibers, opening the door to few-photon applications of quantum communication over long distances.