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Spatial entanglement and topology in semiconductor photonic circuits

M2 Internship / PhD

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Address : 10 rue Alice Domon et Léonie Duquet
Persons in charge of the internship : F. Baboux and S. Ducci Tel : 0157276201 and 0157276225
e-mail : florent.baboux@univ-paris-diderot.fr and sara.ducci@univ-paris-diderot.fr

Possibility to go on with a PhD ? Yes
Envisaged fellowship ? Doctoral school, SIRTEQ, DGA, ANR...

Photonics is playing a key role in the current development of quantum information technologies. The propagation speed of photons and their robustness to decoherence make them an ideal system for quantum communication, while photons are also very attractive candidates for metrology and quantum computation. The current challenge is to attain large-scale applications by miniaturizing and integrating all major components on a single chip. To this end our team exploits the optical non-linearity of the III-V semiconductor platform (AlGaAs) to realize compact sources of twin photons, operating at telecom wavelength and room temperature [1-4].
The goal of this internship/PhD is to develop a novel platfom by coupling together AlGaAs waveguides so as to form periodic arrays of waveguides (Fig. 1a). In these devices, photons can continuously tunnel from one waveguide to the other : they undergo quantum walks, leading to spatially entangled states of light.

Implementing the above concepts, the first objective of the project is to realize a compact and reconfigurable source of spatially entangled photons. Tailoring the pump spatial configuration will allow to control the spatial correlations at the output of the lattice (Fig. 1b-c), and phase shifters will be implemented to dynamically control the lattice parameters and achieve high-fidelity quantum states.
The second objective of the project is to harness the above platform for quantum simulation tasks. The evolution of the quantized electromagnetic field in the waveguide lattice is in direct analogy with the behavior of electrons in a crystall, opening the way to the emulation of various Hamiltonians, in particular with topological properties. We will implement the Su-Schriefer-Heeger (SSH) Hamiltonian, which will allow us to investigate the topological protection of quantum states within a controllable platform.

[1] A. Orieux et al., Phys. Rev. Lett. 110, 160502 (2013)
[2] F. Boitier et al., Phys. Rev. Lett. 112, 183901 (2014)
[3] C. Autebert et al., Optica 3, 143 (2016)
[4] J. Belhassen et al., Appl. Phys. Lett. 112, 071105 (2018)