Digital linearization for broadband multicarrier analog photonic link incorporating downconversion

Abstract

The multicarrier analog photonic links suffer from both the traditional third-order intermodulation distortions (IMD3) and the cross-modulation distortions (XMDs), severely limiting the dynamic range of the links. This paper proposes and demonstrates an effective technique based on a single modulator and photodetector to simultaneously realize the downconversion and receiving of multiple radio frequency signals, as well as suppress the nonlinearities, including the IMD3 and XMD. In the scheme, the nonlinear compensation information is directly obtained from hardware then the distortion compensation is carried out in the digital domain. Experimental results show that the XMD and IMD3 distortions are suppressed with 36.6 and 25.8 dB, respectively, and the link dynamic range is improved by 25 dB, preventing the degradation of the dynamic range of the link. Moreover, the structure of our scheme can eliminate the stringent requirement for hardware.