The realization of ultrahigh-speed communication networks at and above Terahertz (THz) bandwidth is one of today's most challenging problems, as the limiting factors are given by fundamental physical properties and laws. To overcome the restrictions, new concepts and materials have to be invented and utilized. In this laboratory, we investigate the high-speed response of new lasers and materials, as well as passive and active optical systems using ultrashort laser pulses (<100fs) to develop towards higher speed networks. In addition to this, the ultrashort laser techniques in this laboratory enable us to apply many different measurement techniques, accessing the world of the "ultrafast." Time-resolved Terahertz (THz) spectroscopy setup, for example, gives us the unique ability to measure optical, as well as electrical, properties in this ultrahigh-speed frequency region and use it for new and fascinating applications in this new "frequency world."