Abstract For a drastic increase of the optical fiber capacity, extremely advanced optical transmission technologies are indispensable. This chapter reviews such technologies including advanced modulation formants for higher spectral efficiency, transmission technologies using new types of fiber for space division multiplexing, and signal processing technologies providing a variety of functions in high-speed optical transmission systems.

Abstract This chapter describes the design, the transmission characteristics, and the measurements technology of multi-core fibers (MCFs), few-mode fibers (FMFs), and few-mode multi-core fibers (FM-MCFs). Moreover, the cabling technology and future perspectives of innovative optical fiber cable technologies are presented.

Abstract This chapter describes the recent advances in plasma-wave devices for terahertz applications. The first topic deals with nonlinear hydrodynamic properties of massive two-dimensional plasmons in compound semiconductor heterostructure material systems to demonstrate ultrahigh sensitive detection of terahertz radiation and intense broadband emission. The second topic focuses on graphene, a monolayer carbon-atomic honeycomb lattice crystal, exhibiting peculiar carrier transport and optical properties owing to massless and gapless energy spectrum. Theoretical and experimental studies on active Dirac plasmonics in graphene toward the creation of graphene terahertz injection lasers are described.Keywords2D plasmonRectificationInstabilityGrapheneAmplifierLaser