Continuous variables in coupled waveguide arrays

We have transferred our expertise in light flow management in coupled waveguide structures designed and optimized in III-V semiconductors to platforms compatible with on-chip quantum light manipulation i.e. Silicon-on-Insulator and Lithium Niobate. Our aim is to develop sources, circuits and protocols putting to good use telecom armamentarium and integrated optics know-how for quantum photonic circuits that conquer the challenges of stability and scability both in the discrete and continuous variable (CV) regime.  
In the framework of the national project ANR INCQA (INtegrated Quantum Circuits based on non-linear waveguide Arrays) with our collaborators in Nice (InPhyNi S. Tanzilli’s team and Ramtech Iasi, Roumania) we have thus achieved design and/or implementation of compact entanglement sources at 1.5 µm wavelength:

- We proposed versatile entanglement based on a nonlinear directional coupler (NDC) i.e.  continuous-variable entanglement of bright quantum states in a pair of evanescently coupled nonlinear ¬waveguides operating in the regime of degenerate down-conversion and optimization of ressource by exploiting the regime of second harmonic generation. Our schemes result in entanglement in bright or vacuum modes, two-color bipartite and quadripartite entanglement. The proposed device can be realized with current technology in Lithium Niobate and therefore stands as a good candidate for a source of bipartite or multipartite entangled states for the emerging field of optical continuous-variable quantum information processing.

Our goal in the next years is to develop theoretically and experimentally new efficient resources of two-mode and multimode CV entangled states on-chip for optical CV-based quantum technologies using arrays of nonlinear waveguides (ANW) in Lithium Niobate. Following on our recent predictions we plan on the experimental demonstration of telecom bipartite and multipartite CV entanglement on-chip in both NDC and ANW.