Effect on the spectral purity of photon-pairs due to on-chip temporal manipulation of the pump

Photonic Integrated Circuits (PICs) are a promising contender for quantum information technologies. The spectral purity of photons is one of the key attributes of photon-pair sources based on nonlinear optics. We can obtain >99% purity in PIC ring-resonator photon-pair sources by manipulating the pump pulse in the time domain. Here, we have developed a PIC to shape a pulse into dual, triple, and quadruple pulses and investigated the effect of these pump pulse configurations on the purity. Our results show that more complex configurations, compared to a two-pulse configuration, do not result in comparatively higher purity but allow more accurate control over choosing arbitrary values of the purity.