Programmable Integrated Photonics for Quantum Systems

Programmable photonics can find applications in myriad areas including the quantum information field, which encompasses communications, computing, sensing and tomography. Large-scale bulk optics setups previously prevented the development of more complex and scalable quantum optics configurations. Linear optic systems with the required fidelity require a strict control of interference through demanding phase stability mechanisms. Integrating a considerable number of photonic elements on a chip in order to implement multi-port interferometers has become the only viable technological path towards quantum information systems. This chapter introduces the applications of programmable photonics to quantum information systems. After introducing the general framework of a programmable quantum photonic system integrated on a chip and briefly describing the role of more external components such as sources and detectors, it covers the relationship between reconfigurable integrated optic circuits and linear optical quantum gates, quantum transport simulation, boson sampling and complex Hadamard and quantum Fourier transforms.