Optically generated sub-THz continuous wave using feedbacked 3rd order double sideband-suppressed carriers (DSB-SCs)

An optically generated sub-THz continuous wave (CW) using feedbacked 3rd order double sideband suppressed carrier (DSB-SC) is proposed to realize a source of THz communication systems. In this paper, we have generated 3rd order optical harmonics using a 20 GHz microwave local oscillator. We have increased the 3rd order optical harmonics using our proposed optical feedback scheme. Then, they are photomixed by a photomixer for generating the sub-THz CW signals. Comparing with conventional DSB-SC, the amplitude of the 3rd order optical harmonics and the photomixed output power have improved about 15 dB and 25 dB, respectively. Consequently, the proposed technique is very useful for generating sub-THz CW signals using low frequency local oscillators.