Suppression of third-order harmonics in two-tone signals using cascaded Mach-Zehnder modulators

We investigate a technique to suppress undesired third-order harmonics of two-tone lightwave signals using cascaded Mach-Zehnder modulators. Third-order harmonics, which determines the signal-to-noise ratio and side-mode suppression ratio, are dominant spurious components in two-tone lightwave signals. We were able to improve the linearity of modulator and demonstrated 14 dB suppression of third-order harmonics at 10 GHz with the technique.