Quantum integrated photonic circuits

Abstract Integrated quantum nanophotonics aims at combining optical elements on-chip to realize complex circuits with full quantum functionality. Examples are integrated boson sampling circuits and chips that generate 2D photonic cluster states. As such, this modern field of photonics opens up many exciting opportunities in quantum technology with the overarching goal of implementing large quantum networks and photonic quantum computers. This chapter provides an overview of important basics of integrated quantum nanophotonics, represents the state of the art, and provides an outlook on possible future developments. It includes an insight into numerical design and optimization processes and introduces modern manufacturing processes for quantum circuits. Based on this, corresponding circuits relying on homogeneous semiconductor structures are discussed, with a focus on elements with integrated quantum emitters. In addition, advanced concepts are also presented, which are enabled by the heterogeneous combination of different materials in order to develop fully integrated quantum chips. The chapter closes with an outlook on future developments and a summary.