Quantum technologies based on integrated nonlinear devices

Recent achievements in integrated quantum optics and quantum information processing have shown impressive progress for the implementation of linear circuits based on monolithic waveguide structures. However, most experiments are based on χ⁽³⁾ -media, such as glass, silicon-on insulator or silica-on-silicon. In these platforms the implementation of highly efficient sources, frequency converters and fast active phase shifters and modulators pose either severe challenges or appear infeasible for current technologies.

The development of a quantum technology for using of engineered waveguides structures and structures, which harness a χ⁽²⁾ –non-linearity, allows for the realization of devices with tailored quantum functionalities. These include single- and multi-channel frequency conversion with tailored spectral-temporal properties, and complex circuitries comprising degenerate pair generation in orthogonal polarization, linear elements, and active elements such as polarization rotators or an electro-optically controllable time delay. Here we present a review for the implementation of integrated devices based on χ⁽²⁾ –media for quantum circuits and quantum communication systems.