Transfer of a GHz modulation from an optical carrier at telecom wavelengths to a free space THz beam

In order to support the communication needs of our society, carrier frequencies for wireless communication networks in the terahertz frequency range will be an almost forced choice. For instance, the technology of choice to encode high-frequency data signals onto a terahertz carrier is still an open issue. This article investigates the transfer of a gigahertz modulation from an optical carrier at telecom wavelengths to terahertz carrier. Two telecom lasers modulated in amplitude at microwave frequency Omega illuminates an ultrafast ion- irradiated In_0.53Ga_0.47As photomixer. The cw terahertz emission generated by the photomixer is analyzed by using a Fourier transform infrared spectrometer and an Si bolometer. It is demonstrated that high speed modulation of two telecom lasers can be directly transferred onto a cw terahertz carrier frequency generated by the laser themselves, via a photomixing process in an ultrafast In_0.53Ga_0.47As photomixer.