Research On Some Key Techniques Of Integrated Microwave Photonic Radar

Microwave photonics combines the advantages of microwave technology and photonic technology,which can be used for broadband signal generation and processing in radars.However,most microwave photonic systems are established based on discrete devices,which are bulky,costly,and sensitive to environmental variation.Integrated microwave photonics is therefore considered as an important technique to improve the performance of microwave photonic systems,and becomes a hot research topic.In this thesis,several key integrated components or subsystem on chip for radars are studied,including microwave photonics filter,optical tunable delay line,phase shifter and microwave photonic imaging radar.The detailed research contents are as follows:(1)A microwave photonic filter(MPF)and an optical tunable delay line(OTDL)based on a single carrier and a single microring are studied.The center frequency of the MPF and OTDL can be tuned by changing the wavelength of the carrier.(2)In order to solve the limitation of the filter's bandwidth and shape factor in the above method,the MPF based on a single microring and multi-carrier splicing is studied and analyzed by vector sum method.The optimization and reconstruction of the filtering response is realized in an experiment.The multi-carrier splicing method is further extended to broaden the bandwidth of the single microring based optical delay line.(3)An integrated microwave photonic phase shifter(MWP-PS)architecture based on parallel phase modulators and a tunable coupler is proposed based on vector sum method.This method can solve the problem that the polarization-based MWP-PS is difficult to be integrated on a chip.A proofof-concept experiment constructed by discrete devices is carried out to demonstrate the concept.(4)An integrated microwave photonic imaging radar chip is designed,which can realize the frequency-doubling of the transmitted signal and the de-chirp processing of the received signal.The chip is fabricated by Interuniversity Microelectronics Centre.Then the chip is tested preliminarily to verify its feasibility for signal transmission and reception.