The influence of fiber dispersion on the code form of the optical mm-wave signal generated by single sideband intensity-modulation

We have theoretically investigated the transmission performance of the optical mm-wave generation by using an external modulator based on single sideband (SSB) intensity modulation. Though the SSB millimeter (mm)-wave can immune the fading effect, the baseband signals with a high bit rate are degraded greatly after transmission along fiber. The main reason is that the fiber dispersion causes the time shift of the code edges; therefore the maximum transmission distance of the baseband signals is limited. The experimental and simulation results agree well with our theoretical analysis. We also propose a novel scheme to extend the transmission distance. In this novel scheme, the data signals are modulated only onto one of the two optical carriers; hence the shift of the code edges in the down-converted signals after transmission is eliminated.