A fully guided-wave squeezing experiment for fiber quantum networks

Squeezed light is a fundamental resource for quantum communication. In view of its real-world applications, the realization of easy-to-operate experimental systems compatible with existing fiber networks is a crucial step. To comply with these requirements, we demonstrate the feasibility of a squeezing experiment at a telecom wavelength realized, for the first time, in an entirely guided-wave fashion. In our work, the state generation relies on waveguide non-linear optics technology while squeezing collection and transmission are implemented by using only telecom fibre components. By doing so, we observe up to −1.83 ± 0.05 dB of squeezing emitted at 1542 nm in CW pumping regime. The compactness and stability of the experiment, compared to free-space configurations, represent a significant advance towards achieving out-of-the-lab CV quantum communication, fully compatible with long distance operation in telecom fibres. We believe that this work stands as a promising approach for real applications as well as for " do-it-yourself " experiments.