Usually the terahertz source used for terahertz communication is a continuous terahertz wave generated by differential frequency, then can terahertz pulses generated by femtosecond laser be used for terahertz communication?
In principle yes however there is serious problem: how to achieve good sensitivity? To extract information, one needs to perform down-conversion or envelope demodulation / pulse position detection. For Thz continuous wave one can do down-conversion by some kind of mixer however of Thz pulses we mostly left with option of square (envelope) detector and it requires much stronger signal. Some limited distance can obtained by providing rather high power of transmission.