The development of machines that exploit quantum physics to provide fundamentally new computational advantages with respect to conventional or classical hardware is one of most exciting technological prospects for our society. To realise such a computational advantage, these machines will be required to control and process quantum systems at a very large scale, potentially involving millions of quantum information carriers. Single photons, manipulated in linear optical interferometers, are a promising platform to achieve quantum information processing on such a scale. However, the development of photonic technologies able to generate and manipulate photons at this scale has so far proved challenging. This thesis reports recent progress towards large-scale quantum devices based on integrated quantum photonics. We demonstrate the capability of silicon quantum photonics to integrate photonic circuitry comprising hundreds to thousands of optical components interconnected in stable interferometers. We show how, via the scalable integration of both photon sources and circuitry, such devices can be used to generate, control, and process quantum states of light with an increasing number of photons. Finally, we explore the potential of the developed photonic quantum technology to target key quantum applications, such as the quantum simulation of molecular systems and the learning of Hamiltonian quantum dynamics.