Radio Frequency Spectrum Analysis And Multi-frequency Generator Based On Microwave Photonics

As a critical component of modern war, electronic war is playing amore and more important role on the outcome of the fighting. Sincereconnaissance receivers based on microwave photonics have manyadvantages over conventional electronic technologies with aspects likefrequency, bandwidth, dynamic range, electro-magnetic compatibility,power consuming, and volume and so on, they are attracting more andmore interests from both the research community and commercial sectorall over the world. The main works of this dissertation are summarized asfollows:1. The background of microwave photonics based analysis methods forradio signals is introduced and research status of the field is analyzed.Generally speaking, radio signal reconnaissance receivers based onmicrowave photonics make best use of the huge bandwidth offered inthe optical frequency, which have fundamentally broken the limitationof electronic equipment. However, there are still some problem to besolved including flat optical frequency comb generation andminiaturization, integration of the super dense spectrum separationtechnology.2. In conjunction with relevant thesis and other document, we classifyand discuss the three major types of microwave photonics basedanalysis methods which are scanning receiver, instantaneous frequencymeasurement and channelized receiver. The discussion is given byresearching the different mechanisms, presenting typical schemes andanalyzing the strength and weakness of the different types. However， the bottleneck with the super dense optical demultiplexer makes theperformance of direct channelized receivers unsatisfactory. Hence,indirect channelized receivers based on flat optical frequency combsand asymmetric interleavers have been proposed.3. We discuss the different generation mechanisms of the opticalfrequency comb with great details, introduce their great meaning andapplications, and analyze the strength and weakness of different typesof optical frequency combs. Considering our actual use demand, weproposed and demonstrated an optical frequency comb generation withbroadband continuous sweep of the repetition rate based on cascadedphase and intensity modulators. In the experiment, a flat-top19-lineoptical frequency comb with repetition rate continuously sweepingover one-octave from8.5to19.0GHz is obtained. The power deviationmaintains less than4dB without phase or bias rearrangement.4. We introduce a novel method for designing asymmetrical interleaversbased on Michelson Gires-Tournois interferometer in which way wecan obtain all the parameters of the interleavers. Three design instancesare given in the paper. The simulation proves that it is feasible to obtaina interleaver simultaneously with free frequency range of25GHz，and bandwidths within1dB,3dB and20dB of1.6GHz,2GHz and2.5GHz respectively. In the experiment, the measured interleaver hasfree frequency range of12.5GHz and insertion loss of2.8dB,isolation of27dB, and bandwidths within3dB and20dB of1.8GHz,and5.77GHz respectively.5. For conventional electronic channelized receivers, a photonicgeneration of multi-frequency source based on heterodyne of twophase-locked optical frequency combs is proposed and demonstrated.The proposed scheme provides8RF signals whose frequencies spanfrom540MHz to4040MHz with a500-MHz interval. With an opticalphase-locked loop, the phase noise induced by optical links isdecreased by about70dBc/Hz,66dBc/Hz and35dBc/Hz at0.01-Hz, 0.1-Hz and1-Hz offset frequencies, respectively.