The main breakthrough that the uTP4Q project aims to achieve is the development of a unified platform for quantum photonic integrated circuits (QPICs) for quantum communications and quantum computers. We will demonstrate the benefits of heterogeneous integration of different materials by combining InAs quantum dot emitters, Lithium Niobate modulators and switches, and superconducting detectors
in a silicon nitride waveguide interposer. To achieve such seamless integration between different material systems, it is necessary to develop a robust approach for cross-platform integration. Therefore, uTP4Q will use micro-transfer printing as the main technological framework for combining multiple functional technologies for quantum optical processing on a Silicon Nitride waveguide interposer. This is where uTP4Q breaks the ground: for the first time, we will integrate several building blocks of different natures on a single SiN waveguide chip. Once developed, we will prove the performance of our scalable platform by realizing the following unique demonstrations: 1) a plug-and-play single-photon source (SPS) integrated with Silicon Nitride waveguides with >90% coupling efficiency; 2) a lithium niobate pump pulse generator directly integrated with
SPS; 3) superconducting detectors integrated into silicon nitride waveguides for counting photons with a time resolution of 25 ps at a count rate up to 100 MHz, integrated with an on-chip SiN wavelength multiplexer; 4) co-integrating single-photon sources with ultra-high local efficiency detectors to realize a device-independent approach to quantum key distribution.