文摘
In this paper, we have proposed a novel scheme of the radio-over-fiber (ROF) link carrying two 10 Gbit/s 16-quadrature amplitude modulation (QAM) electrical millimeter (mm) wave signal streams. Since the 40 GHz dual-tone optical carrier is generated by frequency quadrupling via a LiNbO3 modulator and the two 10 Gbit/s QAM signal streams are modulated on each tone by single sideband (SSB) modulation with a 10 GHz local oscillator, the frequency requirement of the radio frequency (RF) local oscillators and the optical modulators is reduced to 10 GHz. Because the mm-wave signals in the photocurrent are generated by beating the two second-order sidebands, the 40 GHz optical mm-wave signal has great resistance to the fiber chromatic dispersion. Moreover, the ROF link with the optical mm-wave carrier carrying two 16-QAM 10 Gbit/s data streams has higher spectrum efficiency. To verify our proposed scheme, a ROF simulation link with two 10 Gbit/s 16-QAM SSB optical mm-wave signals is built. The simulation results, including the constellation diagrams, the eye diagrams and the error vector magnitudes (EVMs), show that the transmitted signals keep good performance even after 39 km fiber transmission.