Quantum Optics for Information Technology

QUINTEC - 6934

Work Area: Novel Concepts and New Materials for Optical Devices / All-Optical Computing

Keywords quantum optics, quantum noise, squeezing

Start Date: 28 May 92 / Duration: 36 months / Status: running

Abstract QUINTEC addresses the problems of implementing noise-free light sources, the design of noiseless couplers and amplifiers for more efficient networks, and the search for new concepts of quantum encoding. The work builds on the results of NOROS (3186).

Aims

This project proposes to implement quantum optical techniques for controlling the noise in optical IT, and, beyond this, to explore new concepts which take full advantage of the quantum nature of light.

Approach and Methods

The consortium involves seven partners who represent both academic and corporate research. They bring their skills together to examine three kinds of issues relevant to IT:

Light sources with reduced quantum noise. Based on the expertise developed earlier, several types of such light sources will be studied, laser pumped parametric sources, sub-shot noise lasers and lasers with reduced spontaneous emission.
Noiseless amplifiers and couplers. Using phase sensitive amplifiers and couplers allows to circumvent the 3dB limit set by quantum mechanics for the noise added to the amplified or coupled signal. Several of the most promising systems will be investigated in view of application to on-line all optical noiseless amplifiers, optical taps and optical buses.
Reception, device characterisation and quantum protocols. To investigate the processes described above, the search for materials with very small losses, detectors with high quantum efficiency and low noise electronics is expected to lead to interesting by-products by pushing at the limits of tolerance. On the software side, various kinds of squeezed light and pair photons will be explored with regard to encoding reliability or security in quantum optical information systems.

Progress and Results

Significant results have been obtained in the first year of the project. The emission of squeezed light from second harmonic monolithic resonators can now be stabilised with significant levels of squeezing. Spatial features of squeezing appears to be an new interesting field, worthwhile of experimental investigation, which would lead to noise reduction in images. A high gain noiseless parametric amplifier and a quantum optical tap have been implemented. High efficiency detectors have been designed and used to demonstrate the possibility of quantum communication on long distances.

Potential

Applications of these concepts are expected to lead to: light sources with lower quantum noise; leading to lower BER (bit error rate) in communications; the implementation of noiseless optical buses for information networks, and to the development of quantum encoding.

Latest Publications

Kürz P, Paschotta R, Müller T, Fielder K, Sizmann A and Mlynek J Bright Squeezed Light by Second Harmonic Generation in a douly-resonant monolithic cavity presented at qels'93 postdeadline Session QPD3-1/5
Levenson J A, Abram I, Rivera T, Fayolle P, Garreau J C and Grangier Ph Quantum Optical Cloning Amplifier Phys. Rev. Lett. 70, 267 (1993)
Lugiato L A and Gatti A Spatial structure of a squeezed vacuum Phys. Rev. Lett., to appear
Giacobino E, Courty J M, Fabre C, Hilico L, Lambrecht A Quantum optics with cold atoms Fundamental of Quantum Optics, ed. Elohtzky F (Springer 1993), to appear
Townsend P D, Rarity J G and Tapster P R Single-photon interference in 10km long optical fibre interferometer Electronics Letters 29, 634-5 (1993)

Coordinator

Université Pierre et Marie Curie-CNRS - F
Laboratoire de Spectroscopie Hertzienne
B.P. 74
4 Place Jussieu
F - 75252 PARIS CEDEX 05

Partners

Universität Konstanz - D
CNRS - IOTA - F
CNET - F
INFM - I
Defense Research Agency-RSRE - UK
British Telecommunications plc - UK

CONTACT POINT

Dr. E. Giacobino
tel +33/1 44 27 43 95
fax +33/1 44 27 38 45

QUINTEC - 6934, August 1994

please address enquiries to the ESPRIT Information Desk

html version of synopsis by Nick Cook