Photonic quantum computing is a promising approach, especially because of its scalability to large numbers of qubits, operation of the processors at room temperature and insensitivity to electromagnetic or thermal interference. A very promising and at the same time specific scheme of photonic quantum computing is the measurement-based quantum computation, where processing of quantum information takes place by rounds of simple measurements on qubits prepared in a highly entangled cluster state.

However, the two key challenges are (1) the generation of indistinguishable single photons or states of squeezed light, and (2) maximizing the transmission of all components. Photon loss is always accompanied by information loss. Both requirements can be met by integrated photonic circuits (PICs).

Integrated quantum photonics has greatly evolved in the last decade providing increasingly complex PICs with core functionalities such as generation, manipulation, and detection of quantum states of light. The development of PICs is key for the success of optical quantum information processing and computation as it provides a scalable approach to phase-stable, reconfigurable, and large-scale quantum circuitry.

Stoichiometric Silicon Nitride offers a unique combination of ultra-low loss, tight optical mode confinement, and transparency range that makes it one of the best platforms for integrated quantum photonics as it provides low loss-per-component across that broad transparency range.

We present an overview about architecture, components and challenges of photonic quantum computing and the corresponding challenges to integrated photonic circuits.