Quantum protocols with Si microring at 1.5 µm

We have transferred our expertise in light flow management in coupled waveguide structures designed and optimized in III-V semiconductors to platforms compatible with on-chip quantum light manipulation i.e. Silicon-on-Insulator and Lithium Niobate. Our aim is to develop sources, circuits and protocols putting to good use telecom armamentarium and integrated optics know-how for quantum photonic circuits that conquer the challenges of stability and scability both in the discrete and continuous variable (CV) regime. In the framework of the ANR SITQOM national project (SIlicon phoTonics for Quantum Optics & coMmunication) and in collaboration with L. Vivien’s team (link) and our collaborators in Nice (InPhyNi S. Tanzilli’s team ), we contributed to an efficient energy-time entangled photon-pair source based on four-wave mixing in a CMOS-compatible silicon photonics ring resonator (400 pairs of entangled photons /s/MHz for 500 µW pump power) with a frequency comb structure compatible with standard telecom dense wavelength division multiplexers and optimized waveguide arrays in SOI to achieve record coupling constants despite Silicon high sensitivity to defects.

Our goal in the next years is to create high-dimensional quantum systems with indefinite causal order by using photon-pair source in integrated Silicon photonics. Indefinite causal order is a promising nascent approach for quantum protocols; it results from the control of the order of unitaries involved in a protocol by a qudit. The control qudit in a (quintessentially quantum) superposition state is used to command a superposition of causal order (SCO) of the unitaries, thus enabling new protocols and routes for demonstration of quantum advantage. We want to develop an integrated and scalable SCO implementation based on Si-microrings (fabricated in collaboration with the Silicon photonics group). This activity will benefit for a Marie Curie fellowship on “Indefinite Causal Structures on an Integrated Silicon Platform for Applications in Quantum Computing” starting in August 2018 and the ongoing ANR SITCQOM project.