Uses of Terahertz Measurement in Broadband Connections
Terahertz measurement is widely used to generate terahertz broadband pulses and terahertz narrowband continuous-wave (cw) signals. Since their demonstration as practical THz sources and detectors, THz-PCAs have been the subject of a vast number of scientific and industrial reports investigating their application as terahertz wave transmitters and receivers. In continuous-wave mode, two cw laser beams, with their frequency difference in the THz range, combined either inside an optical fibre or properly overlapped in space, are mixed in a photo-absorbing medium (photomixer) and generate a beat frequency signal. Terahertz signals with the frequency linewidth as low as a few kHz can be generated by photomixers. The frequency of the terahertz signal can be tuned by tuning the wavelengths of the lasers. The output power in conventional photomixers falls from 2 μW at 1 THz to below 0.1 μW at 3 THz. The generation of pulses Broadband terahertz measurement pulses can be generated ...