Research On Millimeter Wave Signal Generation Photonic Vector Modulation And Transmission Performance Based On

Under the general trend of the rapid development of various new technologies,the network traffic is increasing explosively in recent years.In order to meet the requirements of higher transmission rate and transmission capacity,optical over fiber systems are widely used in communication networks.In addition,high-order QAM modulation and millimeter wave signal generation technology are considered key technologies for future communication systems.Because these two technologies often use electrical domain methods for signal processing,there are electronic bottlenecks such as small bandwidth and poor frequency tuning.However,photonic vector modulation and photon-assisted millimeter wave technologies do not need electrical components,which can effectively avoid the impact of bandwidth limitation.So,the millimeter wave signal system based on photonic vector modulation has more advantages than the traditional electronic system.The high-order QAM signal generation scheme of photonic vector modulation,the photon-assisted millimeter wave signal generation scheme and digital signal processing technology are studied mainly in this paper.The main research contents of this paper are as follows:（1）The theoretical research on the generation of high-order QAM signals by photonic vector modulation is carried out.The principles of generating different high-order vector signals based on three schemes of series modulation,parallel modulation and series-parallel hybrid modulation are analyzed respectively,and their respective advantages and disadvantages are discussed.At the same time,we also carried out theoretical research on photon-assisted millimeter wave technology.The application principles,characteristics and applicable places of direct modulation laser method,photonic heterodyne beat frequency method and external modulator method are introduced briefly.Then,the implementation process of single sideband,double sideband and optical carrier suppression based on a single MZM is analyzed,and the corresponding simulation is completed in VPI software.（2）A flexible optical transmitter scheme based on dual-parallel Mach-Zehnder modulator（MZM）and single MZM cascade is proposed.The principle and method of generation and adaptive switching of circular 16QAM,4-amplitude-4-phase 16QAM,circular 32 QAM and 4-amplitude-8-phase 32QAM optical signals are analyzed theoretically.In the VPI simulation environment,the generation and transmission performance of the above four signals under 5Gbaud and 10Gbaud modulation rates are verified respectively.The results show that the transmitter supports the free switching between 8/16/32QAM signals by configuring drive signal（the binary or quaternary）and direct-current bias voltage of the transmitter,and at the same time,the above signals generated have a good signal-to-noise ratio after being transmitted through a certain length of single-mode fiber（SMF）.（3）A millimeter wave signal generation scheme based on photonic vector modulation is proposed.The generation principles of 60GHz QPSK signal,80GHz circular 8QAM and circular 16QAM signal are analyzed theoretically.By building the corresponding optical path system in VPI simulation environment,the successful generation of the above three signals are verified,and the transmission performance of the generated signals in BTB and SMF with different lengths are analyzed and compared.When the modulation rate is 8Gbaud and the bit error rate is reached3.8×10^-3:QPSK signal after 110km SMF transmission consumes 2.8d B more than BTB,circular 8QAM signal transmission under 50km SMF condition loses about 0.7d B compared to BTB,circular 16QAM signal transmitted in the BTB environment improves 1.5d B compared with the 50km SMF,which effectively proves the feasibility of the proposed scheme.