Research On Optical Frequency Comb Generated By Cascaded Modular And Its Appliacation In Mocrowave Photonics

Optical frequency comb(OFC)plays an important role in microwave photonics signal processing with its unique advantages,such as high flatness,frequency stability and ideal correlation.In recent years,the generation of OFC and its application have become research hotspots in related fields.In this paper,the generation and the application fields of OFC based on microwave photonics are studied.The main research contents are summarized as follows:Firstly,a novel scheme based on polarization multiplexing cascaded Mach-Zehnder modulator(MZM)to generate OFC is proposed.The parallel structure of cascaded MZ modulators is used to generate different numbers of OFC,the generation of three groups OFC are realized and verified,which are 25 lines,49 lines and 81 lines flat OFCs respectively.The verification experiment of 49 OFCs is ideal,with flatness of 0.5 d B and sideband suppression ratio of 26.8 d B.Secondly,a flexible and efficient multi-band microwave signal down-conversion scheme based on OFC is presented and demonstrated.The cascaded electro-optic modulator generates two groups of OFC to achieve down-conversion of high-frequency signals to low frequency bands.By changing the spacing of OFC,microwave signal at 30 GHz can be down converted to 2-12 GHz intermediate frequency(IF)signals with a step frequency of 1 GHz.Finally,a channelized receiving scheme based on the generated ideal high-quality OFC is proposed.Based on the use of dual OFC,through the spectrum division of wideband signals,the 7-13 GHz band signal is divided into 7 channels,and the bandwidth of each channel is 1 GHz.