Strong optical cross-phase modulation (XPM) for weak fields is tremendously important for optical quantum information (QI) processing and for all-optical switches in classical communication. A sufficiently large XPM would allow the design of deterministic controlled quantum gates for photonic qubits and thus enable universal optical quantum computation. Recently, several proposals have been brought forward to create large XPM using double electromagnetically induced transparency (DEIT) in which two weak signal light pulses travel at equally slow group velocity, but creating DEIT still poses an experimental challenge. We give a brief overview about DEIT and discuss its applications and limitations. A scheme that combines the best features of previous proposals and optimizes the large XPM parameter for DEIT schemes is outlined. Finally we devise a scheme to perform universal quantum information processing, which respects the bound on the achievable nonlinearity and addresses the requirement of quantum error correction.

Date Published: 29 August 2006
PDF: 8 pages
Proc. SPIE 6305, Quantum Communications and Quantum Imaging IV, 63050H (29 August 2006); doi: 10.1117/12.682572

Published in SPIE Proceedings Vol. 6305:
Quantum Communications and Quantum Imaging IV
Ronald E. Meyers; Yanhua Shih; Keith S. Deacon, Editor(s)