The objective of this project is to make key advances in the development of chip-scale photonic building blocks for the wideband quantum-optical applications. The original idea of this research proposal is to exploit nano-structured multi-layers combined with machine learning algorithms with monolithically integrated waveguides based on Silicon nitride (SiN) material platform. As a main keystone, a system of single-platform photonic building blocks will be demonstrated, relying on broadband optical interconnects, combing high-performance components of photonic system library. The integration will be implemented using multi-layer material waveguides and individual optical elements in SiN platform, enabling the spectral range extension beyond the classical communication wavelengths. The ability to effectively combine more than one spectral waveband into a single platform can enable unprecedented flexibility of system design with a reduced number of components. This demonstration, constituting a breakthrough to establish a chip-scale passive quantum-optical device platform, requires a deep knowledge of different waveguides and photonic material systems. In specific, nano-structured sub-wavelength gratings (SWG) and material multi-layers, so far never explored before, will be studied across a wide range of operating wavelengths.