STAGE Offre de stage : Electrically driven quantum light sources @ Room T

The generation of nonclassical states of light in miniature chips is a crucial step toward practical implementations of
future quantum technologies. For the sake of practicality and scalability, these quantum sources should be easily
produced, operate at room temperature, and be electrically excited and controlled. In this context, AlGaAs present a
strong case for the miniaturisation of different quantum components in the same chip: strong second order nonlinearity
and electro-optics effect, direct bandgap, generation of entangled photons in the telecom band [1-4].
In this project we will build on an electrically injected twin photons source operating at room temperature
demonstrated by our team (Fig a) [2] to push further the capabilities of our devices:
- we will investigate and engineer the quantum properties of the emitted bi-photon state under electrical injection.
Preliminary characterisations show that the signal to noise ratio should allow demonstrating a high quality entangled
state leading to the violation of Bell inequalities (Fig b).
- we will explore the possiblity to develop quantum photonic circuits with new functionalities exploiting the electroopticseffect to
manipulate the generated quantum state.
- we will exploit the cavity effects dues to facets reflectivity to generate frequency entangeld qudits (i.e. quantum units
of information that may take any of d states). Such states present a particular interest since they could directly be used
for quantum information processing in optical fibers, for example to increase channel capacity and security in quantum
communications [5]. Preliminary results (Fig. c) show that our devices generate comb-like spectral correlations
corresponding to entangled frequency qudits with d larger that 100.
The candidate will have the possibility to participate to all aspects of the project, from the clean-room fabrication of
the devices to the quantum optics experiments and the theoretical analysis, in synergy with the theoreticians of our
Quantum Information Technologies team. The work will benefit from our numerous collaborators in France and
abroad.