Effects of the biasing voltage of modulator on the phase noise of opto-electronic oscillator

Low biasing technique has been used recently to reduce the relative intensity noise of the microwave optical fiber links. In this paper, we verify the possibility to reduce the phase noise of opto-electronic oscillator (OEO) by using low-biased optical fiber link. Theoretical and experimental results show that the single sideband (SSB) phase noise of OEO can be reduced mostly by 2.8dB in low biased optical fiber links, compared with conventional quadrature bias of the opo-electronic modulator. The optimal biasing angle corresponding to the minimum SSB phase noise increases with the intensity of the optical carrier.