[en] In quantum mechanics, a measurement influences the quantum state you are observing. While this complicates the investigation of raw quantum states, it might also be used to create interesting new quantum states. In this work, photon subtraction implemented with a single-photon measurement (a particle-like phenomenon) is combined with the interference of two quantum states (a wave-like phenomenon). Resulting complex photon-number correlations of a twomode output state are investigated theoretically and experimentally using coherent states from a pulsed laser and single photons from a spontaneous parametric down-conversion source as the inputs. Furthermore, developments in technology and devices enabling these experiments on an integrated platform, namely titanium in-diffused lithium niobate, are explored. This includes the work on integrating superconducting single-photon detectors on waveguides, the realization of passive integrated optical routing structures, and multichannel interfacing.