Research On Microwave Photonic Frequency Down-Conversion Based On Parallel Electro-Optic Modulators

With the large number of applications of wireless communication,the existing communication frequency band has gradually become saturated and must be expanded to higher frequency bands.But it is difficult to flexibly adjust multi-band signals in the same system and meet the requirements of the future universal multi-band system,due to the limited ability to handle high-frequency signals in conventional microwave frequency conversion systems.Microwave photonic techniques are recently introduced to overcome these limitations because of several inherent advantages,such as potential full-band operation,large instantaneous bandwidth,high RF isolation,low-loss transmission and electromagnetic interference immunity.In the face of the future complex system's design needs,it is very important to research and design the scheme of microwave photonic downconversion system.This subject mainly studied the microwave photon down-conversion technology based on the parallel electro-optic modulator.By comparing the structure and parameters of system in detail using VPI simulation,the performance of the microwave photonic down-conversion system was analyzed and studied.At the same time,a full-band zero-IF microwave photon downconversion system based on parallel electro-optic modulator was proposed.The scheme used optical I/Q modulator to realize carrier-suppressed single-sideband modulation without the adjustable narrowband filter,reducing the power consumption and complexity of system.At the same time,the system frequency conversion performance in this scheme could be stable with 0 GHz to 20GHz spectral range of modulated radio signal:the noise figure was less than 45dB,the spurious spurious dynamic range remained above 105dB/Hz-2/3,I/Q phase imbalance was between-1 and +3 degrees and the EVM of the system was maintained at about 6.6%while the changes remained within 0.4%.The scheme could obviously improve the bottleneck problem of traditional zero IF receiver,such as I/Q imbalance,DC bias and bandwidth limitation.