Quantum enhanced optical fiber sensor – QAFEINE

Fiber optic sensors today represent a widely used solution in many fields of military (navigation, sonar) and civilian (stress and temperature measurements) applications. In terms of pure performance, interferometric devices are the benchmark, thanks in particular to high powers and very low noise laser sources. However, the combination of these two parameters today comes up against inevitable non-linear effects in single-mode fibers, which “saturate” the performance of interferometric sensors. Controlling these non-linear effects is therefore one of the main challenges in the design of new generation optical fiber sensors.

Also, while entanglement is an important resource in quantum information processing or quantum computing, the use of correlations present in photonic “entangled” states is relatively new in the field of fiber optic sensors and interferometric sensors in particular. However, the use of photonic entanglement is clearly an alternative to this pitfall of non-linear effects in fibers. Thanks to optical powers much lower than those of conventional interferometers, the implementation of optical fiber quantum sensors therefore constitutes a serious alternative to all current technologies.

The challenge for QAFEINE is therefore to successfully implement a fiber optic quantum sensor whose performance tends towards that of current conventional devices (few km, µrad / sqrt (Hz), kHz badnwidth), but using extremely low optical powers.

By combining INPHYNI's expertise on entangled photon sources and quantum metrology on the one hand, and TRT-Fr's expertise on the design of innovative fiber optic sensor architectures for the detection of acoustic waves , and for navigation on the other hand, the objective of QAFEINE is twofold:
- Design a quantum optical fiber sensor (CQFO) architecture that responds to dual applications and whose principle is interference between pairs of entangled photons at telecom wavelengths.
- Strongly improve the performance of this CQFO in terms of sensor length, required optical power level, and bandwidth, by optimizing the entangled quantum state which makes it possible to probe the sensor (entanglement in energy time, and / or in polarization).

This optimization of the photonic quantum state in order to improve the performance of CQFOs is a strong and still unresolved problem in the field of quantum sensors in general. It is therefore central in QAFEINE.

In addition, this project will compare the performance of the same device probed with classical light or with a quantum entangled state. This project will therefore make it possible to provide quantitative and experimental answers to concrete application cases for which certain optimized quantum photonic states make it possible to envisage an alternative to the classical states of light in the rapidly expanding field of fiber optic sensors.

In the longer term, this project will therefore make it possible to design new generation sensors for dual applications (navigation, sonar, etc.) and for which absolute control of the level and form of photonic entanglement is essential.

The advances demonstrated within the framework of this project will directly benefit the underwater listening and navigation systems developed by Thales, within the DMS (Defense Mission Systems) and AVS (AVionic Systems) divisions. The concepts studied as well as the components identified for future developments could also contribute to the improvement of quantum communication systems, at the heart of the concerns of Thales SIX and Thales Alenia Space, for example.