Radio frequency carrier signal generation using a single Mach-Zehnder Modulator based optical comb generator

Creating a radio frequency (RF) signal from the optical domain is a widely used technique for THz signal generation. The RF signal is obtained applying two optical carrier signals by photomixing in a photodiode. Because of the quadratic characteristic of the photodiode the frequency difference of the two lasers will appear in the electrical spectrum. There are two kinds of optical sources for photomixing. We can use two independent lasers at different wavelengths or an optical comb source.