A device for generating or receiving electromagnetic radiation in a frequency range from 10 GHz to 100 THz is provided. The device includes a housing and a wave guide fiber leading into the housing. The wave guide fiber is adapted for guiding pulsed laser light with a first central wavelength. Within the housing, a terahertz converter is provided for generating or receiving the electromagnetic radiation in the terahertz range. The device also includes a frequency converter for converting the light exiting from the wave guide fiber to a second central wavelength being arranged between the end of the wave guide fiber and the terahertz converter in such a way that the terahertz converter is impinged by the frequency converted light.