Tools for Multimode Quantum Information: Modulation, Detection, and Spatial Quantum Correlations

We present here all the tools required for continuous variable parallel quantum information protocols based on spatial multi-mode quantum correlations and entanglement. We describe techniques for encoding and detecting this quantum information with high efficiency in the individual modes. We use the generation of spatial squeezing light in higher order transverse Hermite-Gauss modes as a demonstration of the quality of our scheme. The squeezing in selective modes is achieved by fine tuning of the phase matching condition of the nonlinear (2) material and the cavity resonance condition of the optical parametric amplifier. By combining these modes we can now build a practical multi-mode optical quantum information system.