Research On Microwave Photonic Broadband RF Receiving Technology Based On Multi-frequency Optical Local Oscillators

The next generation of RF systems,such as radar and electronic warfare,are developing towards the comprehensive integration of general purpose,multi-band,ultra-wideband and multi-function,which puts an urgent need for the large instantaneous operating bandwidth to RF receiver.Thanks to the benefits in terms of large bandwidth and parallel processing,the photonic technology can help break through the electronic bottleneck of traditional microwave devices.Therefore,the construction of broadband RF receivers based on microwave photonics technology has become an important development direction and has important research significance.In view of this development trend,this paper studies the microwave photonics broadband RF receiving technology,which is based on multi-frequency optical local oscillator,and mainly carries out the following aspects of work:1.Theoretical analysis and derivation of various performance parameters of wideband channelized receiving technology based on dual optical frequency combs,including the influencing factors of the channel numbers and efficiency,research on the requirements for key features like multi-frequency and microwave photonic mixing by improving the channel number and efficiency.2.Aiming at the demand of multi-frequency optical local oscillator for microwave photonic channelization technology,a multi-frequency optical local oscillator generation scheme based on partial demultiplexing structure is proposed and studied: theoretical analysis of the generation mechanism of multi-frequency optical local oscillator that is based on partial-division multiplexing structure,by introducing the polarization parameter,reduces the requirement of RF power,effectively increases the number of generated local oscillators,and simulates the relevant theoretical derivation;on this basis,the experimental system for the generation of multi-frequency optical local oscillator is built,the experiment achieves multi-frequency optical local oscillator with up to 13 comb lines,with the RF power less than 28.4 dBm and flatness better than 2.7 dB.3.The channelized receiving scheme based on multigroup multi-frequency optical local oscillator and microwave photonic image frequency rejection mixing is proposed and studied,which effectively improves the number and efficiency of channels: by expanding the group number of multi-frequency optical local oscillator,the number of achievable channels can be effectively improved,and the channel crosstalk can be suppressed by introducing microwave photonic imagefrequency rejection mixing.The theoretical analysis and derivation of the scheme was carried out,and an experimental verification system was built.The experiment completed the channelized reception of8 channels for a 20-28 GHz wideband signal,each channel having a bandwidth of 1 GHz.4.Using the dual output characteristics of the bridge,a multi-group optical frequency comb based on the polarization-multiplexed dual-output structure and a channelized receiver with optical domain image-suppressed mixing are designed.Under the condition of only two fundamental vibrations,the realization is realized.The 8-channel reception of the 8-12 GHz wideband chirp signal further reduces the number of local oscillators.The channel bandwidth is 500 MHz and the single-channel image rejection is up to 33 dB.