Optical Fiber Transmission And Frequency Conversion Of RF Signals With Large Dynamic Range

High linearity RF signal transmission and frequency conversion link are important components in modern broadband radar,wireless communications,satellite communications,electronic warfare,and other electronic systems.With the advent of the 5G era,various new types of information industries have emerged.The amount of information and data on the"Information Superhighway"is growing explosively.High frequency,wide bandwidth,large dynamic range,large transmission capacity,and high transmission rate are becoming the development trend of the modern electronic system.However,due to material and process level limitations,traditional electronic systems suffer from severe electronic bottlenecks in terms of operating frequency,transmission bandwidth,and signal processing speed.And there are also problems such as large loss and susceptibility to electromagnetic interference,which makes it difficult to keep up with the current development of theoretical technology and cannot meet the development needs of future electronic systems.The microwave photonics has become a current research hotspot because of its unique advantages such as low loss,high operating frequency,large bandwidth,and immunity to electromagnetic interference.However,current Radio over Fiber（Ro F）and microwave photonic frequency conversion systems generally have problems of low gain and small dynamic range,and focus on the performance of the overall link,ignoring the impact of each component on the overall system.Thesis aims at the problems existing in the technology of Ro F and microwave photonic frequency conversion,starting from the basic components,the key component models are established,and the relevant technical indicators are analyzed.and an RF signal transmission and frequency conversion technology through fiber with large dynamic range is explored.The specific research work in this paper mainly has three aspects.（1）The key component models of Ro F and microwave photon frequency conversion links are established.The key components of the Ro F and microwave photonic frequency conversion link,such as laser,electro-optic modulator,optical fiber,and photodetector,are introduced in detail,and the transmission models of several devices are obtained using mathematical closed loop formulas.The main technical indicators of the link are theoretically derived and analyzed,such as gain,noise factor（NF）,third-order intermodulation distortion（IMD3）,spurious free dynamic range（SFDR）and adjacent channel power ratio（ACPR）,ect.（2）The overall theoretical model of direct modulation and external modulation Ro F links is established.In view of the lack of device-level and underlying physical link models in current microwave photonics,a complete mathematical model of Ro F links with direct modulation and external modulation are established,and the technical indicators of link gain,NF,and SFDR are analyzed in detail.The optical simulation software VPItransmission Maker9.8 was used to simulate and test the various indicators of the two links,and compared with the theoretical modeling formula in detail.After verification,the theoretical model agrees well with the simulation results.（3）A large dynamic range microwave photonic frequency conversion technology based on PDM-DPMZM is proposed.After comparing and analyzing three kinds of photonic frequency conversion schemes based on MZM in theory and simulation,combined with the advantages of external modulation Ro F links and existing linearization methods,a large dynamic range microwave photonic frequency conversion technology based on polarization multiplexing dual parallel Mach Zend modulator（PDM-DPMZM）is proposed.Related simulation results show that the system can realize the optical fiber transmission and frequency conversion function of the RF signal at the same time,and can get a frequency conversion gain of about–30 d B and an SFDR improvement of 20 d B,compared with the system without linear optimization and without optical power amplification.The final SFDR can reach 128.1 d B*Hz^（2/3）.