Research On UWB Signal Generation And Transmission Technology Based On Microwave Photonics

Microwave photonics is an emerging interdisciplinary subject that combines microwave technology and photonic technology.It uses optical equipment and technology to generate,process,control and transmit high-frequency microwave signals,with large bandwidth,low loss and light weight.,anti-electromagnetic interference and other advantages,has been widely used in wireless communication,radar,sensing,imaging and instruments and other fields.Due to the large bandwidth of photonic technology,it can break through the bandwidth limitation of traditional radio frequency systems.Therefore,microwave photonics is a generation and propagation technology with great potential.Ultra Wideband is a wireless communication technology.It does not need to use a sinusoidal carrier,but uses a nanosecond-level narrow pulse width non-sinusoidal signal for data transmission,so it has a large bandwidth and is suitable for high-speed communication.UWB has the characteristics of high bandwidth,fast transmission rate,long transmission distance and low loss.The new method of obtaining UWB by microwave optical technology is the current research hotspot.The first part of the thesis briefly expounds the background and significance of the generation and development of ultra-wideband over optical technology,explains the advantages of directly generating ultra-wideband signals in the optical domain,and then introduces the basis of the process of generating ultra-wideband signals Theory and key devices.A simple-structured second-order ultra-wideband signal generator is proposed.By constructing a microwave photonic filter,the conversion from PM-IM is realized,and the Gaussian pulse is first-order differentiated.By constructing a microwave photon delay line filter,the first-order ultra-wideband signal is differentiated to generate a second-order ultra-wideband pulse.The simulation verification is carried out by Optisystem software,and experimental verification takes place in a laboratory.The generated second-order UWB signal has a pulse width of 240 ps,and the spectrum has a center frequency of about 5.4 GHz and a 10 d B bandwidth of 4.6 GHz,with a relative bandwidth of 85.2%.In order to further improve the transmission performance of ultra-wideband signals and enhance the anti-interference ability,a light-borne ultra-wideband system transmission technology is proposed,which comprehensively uses multi-pulse modulation technology,dispersion compensation technology and encoding and decoding technology.After simulation verification by Opti-system and Matlab software,when the forward error correction threshold is 3.8×10-3,the receiver sensitivity is increased by about 5.5d Bm.This technology effectively reduces the bit error rate of optical UWB system transmission and further improves the performance of optical UWB transmission system.Finally,it summarizes the completed work,presents the main difficulties in this field,and looks forward to the possible further research directions in the future.