Silicon Photonics for Quantum Fibre Networks

Nowadays secure communication is essential for exchange of sensitive information, while the security based on classical cryptography protocols cannot be absolutely guaranteed. Especially when a full-tolerant quantum computer will be available, the classical encryption and decryption methods will be no longer secure [1], posing a serious threat to cryptosystems. Quantum cryptography (QCy), a branch of Quantum Communications (QCs), has opened a new era in the security of information transmission.

Although big steps in QCs and Quantum Key Distribution (QKD) have been taken over the last 20 years, the future of QCs is stillchallenged by major barriers. The SQUARE project shatters these barriers by developing the next generation of quantum devices based on silicon photonics, enabling compact, reliable,and efficient components, allowing for the construction of fully connected long-reach, high-rate QKD-secured quantum communication networks.The SQUARE project develops a fully integrated transmitter (Tx) and receiver (Rx) for quantum communications and classical communication based on silicon photonics, which is a powerful means to combine the assets of integrated photonics with CMOS technologies. The driving force behind silicon photonics is that silicon represents a mature integration platform, which brings photonic circuits to a higher integration level allowing for mass-production [2,3] as it has done for electronic circuits. In this sense, we believe that silicon photonics will play a significant role in future QCs, allowing to build up powerful and cost-effective photonic circuits for quantum communication applications. SQUARE will develop the integrated quantum technologies necessary to breach the limits of current state-of-the-art, and furthermore integrate these technologies directly in quantum subsystems. Hence the components will be developed for specific applications in specific quantum network scenarios. The proposed novel network leverages on the strengths ofdifferent technologies to obtain global benefits in terms of reach, sensitivity, complexity,practicality and total power consumption.


  • Coordinator: Karsten Rottwitt (Technical University of Denmark, DK)
  • Peter Tøttrup (IrSee, DK)
  • Guang-Hua Duan (III-V Lab, FR)
  • Ségolène Olivier (Commissariat à l'Energie Atomique et aux Energies Alternatives, FR)
  • Alberto Tosi (Politecnico di Milano, IT)
  • Alessandro Ruggeri (Micro Photon Devices, IT)
  • Mark Thompson (University of Bristol, UK)
  • Muhammet Ali Can (Tubitak Bilgem, TR)