Possibilities and limits of Terahertz-waves for communications systems of tomorrow
Möglichkeiten und Grenzen von Terahertzwellen für zukünftige Kommunikationssysteme
The capacity of existing communications channels (e.g. the maximum bitrate which can be transmitted), is no limit for today's applications. Thus, new technologies for spectral efficient modulation, the reduction of noise or distortions were sufficient to cover the data increase rates of 40% per year. Recently in photonic networks the possible limits came within sight. At OFC 2010 with today's forefront technologies (spectral efficient modulation, distributed Raman amplification, suppression of nonlinear effects via nonlinear SchrÃ¶dinger equation) data rates which reach the limits of the optical fiber systems have been shown. Since an end of the data increase rates cannot be seen, completely new approaches are needed to offer the capacity requirements in the networks for worldwide communications. One possibility is the exploitation of new frequency ranges for data transmission. In the Terahertz range of the electromagnetic spectrum a large unregulated bandwidth is avail able. At the same time THz-waves have transmission properties which are between that of radio- and optical waves. Thus, new broadband transmissions and applications with GHz bandwidths are possible in the currently unregulated THz spectral resources. In this article the physical properties of THz-waves will be described. An overview of projects in this frequency area will be given and it will be shown how THz-waves can be used for future communications systems.