Optically Filtered Microwave Photonic Links for RF Signal Processing Applications

The performance of filtered analog photonic links, useful in signal processing applications, is analyzed along with techniques for compensation of distortion. We analyze the attributes of various link configurations and compare the performance of filtered coherent-detection links with intensity-modulated-direct-detection links. Experimental results on the dynamic range and the compensation of nonlinearities using predistortion compensation are presented for a filtered coherent link. We demonstrate suppression of third-order nonlinearity by 20 dB. In addition to supporting signal processing operations such as filtering and arbitrary intermediate frequency downconversion, at the same detected power, we find filtered coherent links to have up to 9 dB noise figure advantage over unfiltered direct-detection links, dependent on the limits of the operating optical power in the link.