Ad­vanced In­teg­rated Quantum Cir­cuits

Integrated optical devices in LiNbO3 have been developed since almost 40 years. In the past decades a multitude of devices has been demonstrated. Some of them – in particular electro-optic modulators – have become successful commercial products. Most of the device developments in the past were dedicated for applications in telecommunications. Our vision is to benefit from these experiences and adapt them to the challenging demands required for quantum optical applications.

By developing efficient and specifically tailored PDC sources the potential of integrated quantum devices in LiNbO3 is by far not completely exploited. For the future we see a promising potential of developing much more complex integrated quantum circuits.

Our goal is to integrated nonlinear PDC sources with passive routing elements (e.g. 3 dB couplers, beam splitter, space switch and polarization beam splitter) and actively controllable electro-optic components (e.g. phase-modulators or polarization convertor) on a common substrate to realize application specific integrated quantum circuits.

Although we are aware that the capability to fabricate such complex quantum circuits still requires substantial future research work, first steps towards this direction are currently already under progress. One example of a sample recently developed is shown in Fig.