The Fraunhofer-Gesellschaft undertakes applied research of direct utility to private and public enterprise and of wide benefit to society. The Fraunhofer-Gesellschaft currently maintains 56 research institutes at 40 different locations throughout Germany. The core competence of the Fraunhofer Institute for Telecommunications, Heinrich-Hertz-Institute (Fraunhofer-HHI) is in the areas of photonic networks and components, mobile broadband systems, fibre optical sensor systems and electronic imaging technology for multimedia. In its three main working areas Fraunhofer-HHI is a valued partner in national and international co-operative R&D projects. Fraunhofer-HHI has about 250 employees and app. 80 students as R&D assistants. The objective of research in the photonic networks area is to make substantial contributions to the development of photonic networks and advanced photonic components. Fraunhofer-HHI has been involved in optical transmission research from the very beginning. Longstanding expertise exists also in InP-based photonic components and photonic integrated circuits, complemented by silica on silicon and polymer devices. Along with this expertise, a full range of design, modelling, measurement, and experimental capabilities exists for photonic networks. In the area of access optical networks the work addressed in particular the topic of cost-efficient fibre based subscriber lines and the use of wavelength division multiplexing. Further activities were related to broadband home area networks and optical wireless communications. Fraunhofer-HHI participated(s) in various European and national research projects and programs (e.g. MUSE, e-PHOTON/ONe, BONE, NOBEL, Eibone, 100GET, OMEGA, EUROFOS, OCEAN, FIT).