High-dimensional photonic quantum systems promise a change of paradigm for various applications in information processing systems, for example in advanced communication systems and in high-performance computing and simulation of quantum systems. They can shift the boundaries of today’s systems and devices beyond classical limits and seemingly fundamental limitations. The use of complex photonic systems, which comprise multiple optical modes as well as nonclassical light, has been proposed in various theoretical works over the last decades and illustrate the versatility of photonic systems. However, the implementation of scalable architectures requires advanced setups of high complexity, which poses considerable challenges on the experimental side.

Here we present an overview for advancing current experimental approaches for scaling multi-dimensional photonic quantum systems. These comprise non-linear integrated quantum devices, source engineering and pulsed temporal modes as well as time-multiplexed architectures.