Quantum interference is a powerful instrument in modern quantum optics that can be used for precise time and phase measurements, generating entanglement and testifying non-locality of entangled systems. Nonlinear interferometry provides a new insight into quantum interference. A non-linear (SU(1,1)) interferometer can be obtained from a conventional linear interferometer by replacing the beam splitters with nonlinear media. Such interferometers indicate stability to the external losses and, at the same time, show an improvement in the phase sensitivity compared to their linear counterparts. Nonlinear interferometers are useful tools for creating single-mode sources and providing spectral engineering of light with different intensity profiles and mode contents. The interaction of matter with quantum light generated in the parametric down-conversion process and nonlinear interferometers leads to new phenomena which cannot be explained by semiclassical approaches. This talk will highlight our recent advances in quantum multimode nonlinear interferometers, their integrated implementations, generation of bright squeezed states of light with strong correlations within nonlinear interferometers, as well as in the interaction of matter with specific quantum states of light and new phenomena arising within such interaction.