Quantum Projectors Implemented With Optical Directional Couplers in Ion-Exchanged Glasses

Abstract

Ion-exchanged glass as a platform for quantum photonics is proposed. Quantum projectors are implemented with integrated optical directional couplers fabricated by ion-exchange K + /Na + in soda-lime glass. We consider devices composed of concatenated directional couplers which implement N -dimensional quantum projective measurements, and concomitantly the production of 1-qudit states. The fundamental units of these devices are 2 × 2 directional couplers that are experimentally studied in order to obtain, through an optical characterization, empiric relationships between fabrication and optical parameters of such couplers. Likewise, a two-dimensional quantum projector is demonstrated so that projective measurements are obtained for the states of bases X (diagonal) and Y (circular).Index Terms-Integrated quantum passive elements, integrated quantum projective meters, ion-exchanged glass platform. I. INTRODUCTIONI NTEGRATED quantum photonic devices can implement different quantum operations for quantum communications, quantum computation, quantum metrology, and so on, with the inherent advantages associated to integrated optics. Different platforms have been proposed and used to develop these integrated quantum devices, including silicon-on-insulator (as SiO 2 ), Lithium Niobate, and Gallium Arsenide [1]-[3]. However, to our knowledge, ion-exchanged glass (IExG) platform has not been used as an integration technology for quantum photonics, despite the fact that it is present in many classical optical communications systems and optical sensors, and has been