Photonic communication networks with integrated QKD

Photonics is a key enabler for the modern ICT infrastructure and provides – barely visible for the end user – the backbone of the Internet. The business unit “Optical Quantum Technology” addresses photonic communication networks in view of next-generation metro-access network architectures and, moreover, the integration of quantum technology in classic telecommunication networks. A representative example is the integration of quantum key distribution (QKD) in information-theoretically secure metro-access networks.

  • In the framework of the WWTF project LQuNet a reflective QKD system based on DPS (Differential Phase-Shift) is developed. LQuNet aims at applications in Passive Optical Networks (PON) and Local Area Networks (LAN). The QKD system is conceptually laid out in a way that complexity and cost is centralised at a shared line terminal acting as the (Alice-side) head-end of the QKD links. In this way, economically viable deployment of low-cost (Bob-side) QKD transmitters based on telecom-grade components can be guaranteed.
  • The seamless integration of QKD systems in existing and next-generation metro-access architectures is performed under the umbrella of the FFG project QKD-TELCO. Polarisation-entangled QKD is applied in combination with multiplexing technology in order to guarantee high secure key rates without the use of a separate transmission fiber for quantum channels. The overall communication link is designed in a way that existing and arising PON standards (GPON/EPON, XGPON/10G-EPON and also NGPON2) can benefit from a simultaneously present secure link for key generation, as do metro networks where amplified DWDM links co-exist with QKD channels.
  • The EU-funded WARP-5 project addresses a next generation of quintuple-play metro-access networks based on coherent PON technology. The migration towards low-complexity coherent detection, ultra-dense WDM (Wavelength Division Multiplexing) and advanced optical modulation (up to 16-QAM) provides a unique asset for Fiber-to-the-Home networks. High guaranteed data rates up to 10 Gb/s for each end-user, high compatible loss budgets for PON splits of 1:1000 and an extended reach of 100 km well in line with metro-access convergence are just a few of the advantages that coherent PONs can offer.