Quantum Cryptography(Module 1&2)

Jean-Marc Mérolla, Yuri T. Mazurenko, J.-P. Goedgebuer +2 more

We describe a new method for quantum key distribution that utilizes phase modulation of sidebands of modulation by use of integrated electro-optic modulators at the transmitting and receiving modules. The system is shown to produce constructive or destructive interference with unity visibility, which should allow quantum cryptography to be carried out with high flexibility by use of conventional devices.

Αντώνιος Κ. Παπαδόπουλος

Laurent Duraffourg, Jean-Marc Mérolla, J.-P. Goedgebuer +2 more

We report a new transmission that can be used for quantum key distribution. The system uses single-sideband-modulated light in an implementation of the BB84 quantum cryptography protocol. The system is formed by two integrated unbalanced Mach-Zehnder interferometers and is based on interference between phase-modulated sidebands in the spectral domain. Experiments show that high interference visibility can be obtained.

Jean-Marc Mérolla, Yuri T. Mazurenko, J.-P. Goedgebuer +1 more

We report single-photon interference in the sidebands of modulated light. The relative phase of interacting quantum states is reliably controlled by the phase of a low-frequency modulating signal. We show how this type of interference can be used to build a robust system for quantum cryptography. An experiment was implemented at 1540 nm, over a 20-km-long standard single-mode fiber, using a germanium singlephoton avalanche photodiode.

Dr. Revanesh M Dr. B. S. Sahana Raj