A microwave photonic link with high spurious-free dynamic range based on a parallel structure

A microwave photonic link （MPL） with high spurious-free dynamic range （SFDR） is proposed and analyzed. The optical carrier is divided equally into two paths. The path I is modulated by radio frequency （RF） signals in a Mach-Zehnder modulator （MZM）, and the phase of path 2 is controlled before the combination with path 1. By properly adjusting the phase difference of the two paths with the optical phase shifter, the third-order intermodulation distortion （IMD3） can be significantly suppressed. A proof-of-concept simulation is carried out. The results show that a reduction of 40 dB in the IMD3 and an improvement of 21.1 dB in the SFDR are achieved as compared with the conventional MZM-based MPL. The proposed MPL shows the advantages of simple structure, low cost and high efficiency.