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Silicon Quantum photonics

​​​​​​​​​Developing components for quantum communications and computing​

Published on 3 November 2023


Silicon Quantum photonics ​​

Developing components for quantum communications and computing​

Quantum photonics is key to ensure ultra-safe data transmission. It also has recently emerged as a potential path towards quantum computing.​​​

Ensuring large-scale integration is necessary to enable quantum applications. To achieve massive integration, CEA-Leti leverages its mature Si and SiN photonics platform for the development of low-loss quantum photonic hardware. ​

CEA-Leti specifically develops quantum-grade photonic integrated components & circuits for the generation, fast encoding, coherent manip​​ulation & detection of photonic qubits. CEA-Leti components are compatible with discrete or continuous variable approaches.

The goal?​​​​

CEA-Leti aims at contributing to the future generation of miniaturized ultrasecure quantum communication systems, either fiber-based or in free-space, by developing integrated quantum transmitter and receiver circuits matching the specifications of the most advanced quantum communication protocols, such as device-independent ones. 

CEA-Leti also aims at contributing to the development of integrated quantum photonic processors relying for example on measurement-based quantum computing protocols. We address the heart of the programmable quantum processor while ensuring seamless generation of entangled photon cluster states and their high-efficiency detection on-chip.​​

What does it require?​​

CEA-Leti’s experts are developing key integrated components and circuits to enable advanced quantum key distribution protocols and quantum processing:​

​Single photon generation

  • Hybrid III-V/Si lasers delivering weak coherent pulses [1]
  • High-Q ring resonators delivering heralded single photons (currently MHz rate, targeting GHz rate)[2]

Photon fast encoding and coherent manipulation

  • Loss-free thermo-optic phase shifters
  • Fast phase shifters based on free-carrier plasma dispersion
  • Towards fast & low-loss Pockels phase shifters

Single photon detection

  • HgCdTe avalanche photodiodes[3] with a world-record speed for the detection of mesoscopic photon states
  • Optimized NbN material[4] for superconducting nanowire single photon detectors with high efficiency and low dark counts​



1. C. Agnesi et al., Hong-Ou-Mandel interference between independent III-V on silicon waveguide integrated lasers, Opt. Exp. 44, 271 (2019)​
2. H. El Dirani et al., Low-loss silicon technology for high-Q bright quantum source, proc. of IEEE Group IV Photonics Conference (2019)​
3. J. Rothman et al., Meso-photonic detection with HgCdTe APDs at highcount rates, J. of Electron. Mat., https://, 2020​
4. R. Rhazi et al., Improvement of critical temperature of niobium nitride deposited on 8-inch silicon wafers thanks to an AlN buffer layer, Superconduct. Sc. and Technol. 34, 045002 (2021)​

​CEA-Leti’s quantum photonics platform enables the development of next-generation technologies for key industries such as:

  • Finance​
  • Health care​
  • Energy​
  • Teleco​mmunications
  • Defense.​​
​​​Key facts​​​ 

State of the art capabilities

  • Design, Process integration in 200/300 mm, Test, Packaging

Versatile platform

  • Comprehensive library of mature components @ 1310 and 1550 nm
  • Integration of new materials (NbN, LiNbO3…)​

Record low optical losses

  • Si waveguides: 0.2-1.1 dB/cm
  • SiN waveguides: 0.05 dB/cm​​
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