An Analog Photonic Down-Conversion Link With Simultaneous IMD3 Distortion Suppression and Dispersion-Induced Power Fading Compensation

A novel analog photonic down-conversion link based on a polarization modulator and a phase modulator with simultaneous linear optimization and chromatic dispersion-induced power fading compensation is proposed and experimentally demonstrated. By introducing an appropriate phase shift to the optical sidebands, chromatic dispersion-induced power fading is compensated, and third-order intermodulation distortion terms are eliminated in the same time. The scheme exhibits wide operating frequency range due to its no use of filters and frequency-dependent electrical or optical devices. The scheme is robust, as the operation of the polarization modulator and the phase modulator are independent of signal amplitude and bias voltage. Experimental results show that, for a 25-km transmission link, an improvement of more than 15.5 dB in spurious-free dynamic range is achieved and the dispersion-induced power fading is compensated at the same time. In addition, benefiting from the power compensation and significant suppression of IMD3, a 16QAM vector signal is demonstrated to have a good demodulation performance.