A Linearized Analog Microwave Photonic Link With an Eliminated Even-Order Distortions

An improved linearized analog microwave photonic link (AMPL) with significant multioctave bandwidth performance is experimentally presented. The proposed AMPL configuration is based on a double dual-parallel Mach-Zehnder modulator and a differential balanced photodetector (BPD). Explicitly, a gallium arsenide (GaAs)-based modulators are used as opposed to the commonly known lithium niobate (LiNbO3) modulators, due to its robustness in the harsh environment. The system configuration is designed to process a carrier suppressed double-sideband signal through the link, and then at the receiver, a carrier suppressed double-sideband signal is combined with an unmodulated optical carrier, which is transmitted through a polarization maintained (PM) optical fiber. In our experiment, only PM-based optical components are used for better system stability. The developed theoretical model of the proposed system illustrates the elimination of even-order distortions and a high suppression to the third-order intermodulation distortions at the BPD. Consequently, the fundamental signal to interference ratio of 60 dB was experimentally achieved. Furthermore, experimental results, simultaneously, demonstrate a significant increase of second-order spurious-free dynamic range and third-order spurious-free dynamic range by 19.5 and 3.1 dB, respectively, compared to the previously reported AMPL performances based on polarization multiplexing dual-parallel Mach-Zehnder modulator. To the best of our knowledge, this is the highest dynamic range AMPL system performance deploying GaAs electro-optic modulator which has most significant capabilities in managing RF signals and exhibits excessive performance in harsh operating environment in terms of thermal stability, power-handling, radiation resistance and longevity for aerospace, defense, and satellite-to-ground downlink communication system applications.

Automated summary

An improved linearized analog microwave photonic link (AMPL) with a significant multioctave bandwidth performance is experimentally presented in this study. The system configuration is designed to process a carrier suppressed double-sideband signal through the link, demonstrating a fundamental signal to interference ratio of 60 dB. The use of gallium arsenide (GaAs) modulators instead of lithium niobate (LiNbO3) modulators provides better system stability and performance in harsh operating environments.