Quantum photonic technologies offer the possibility of exploiting the fundamental principles of quantum physics in order to implement unbreakable communication protocols, reaching unprecedented sensitivity in measurements and delivering humongous computational power.

A typical quantum photonic system encompasses three fundamental tasks: resource state generation (based on single-photon sources), quantum state manipulation (based on interferometric circuits) and photon state measurement (based on single-photon detectors). In this scenario, the integration (either monolithic or hybrid) of all these components plays a key role, guaranteeing unrivaled scalability to the eventual application.

The Hi-Light (Hybrid Integration of Laser-written Interferometers and sinGle pHoton deTectors) project holds the potential to provide an experimental breakthrough in the integration of programmable photonic circuits exploiting a hybrid approach. Femtosecond laser written waveguides fabricated on glass substrates will be directly combined with arrays of single photon detectors, i.e. single photon avalanche diodes (SPADs).

The exploitation of custom technologies both for photonic circuits and single photon detectors will allow us to explore novel 3D geometries for programmable photonic circuits with great scalability perspectives. Silicon SPAD detectors fabricated with a custom process can provide high sensitivity in the near infrared and can be operated at room temperature allowing a direct coupling with the photonic circuit.

The key objective pursued in this project is the development of an integrated photonic platform able to implement an arbitrary optical transformation on a high number of modes (up to 64) with embedded single-photon coincidence electronics.

The research will be coordinated by Dr. Francesco Ceccarelli at the Istituto di Fotonica e Nanotecnologie of Consiglio Nazionale delle Ricerche (CNR-IFN) in Milan.