Research On Integrated Microwave Photonic Filter Based On Stimulated Brillouin Scattering

The rapid development of modern science and technology has brought people a better life.Especially after entering the information age,network communication and mobile communication have brought great convenience to people.For traditional communication systems,it is usually an electronic circuit-based communication system.We call it an electrical system.With the rapid advancement of modern communication technology and the development of the Internet,the amount of information is exploding,so there is a higher communication system claim.Due to its unique electrical bottleneck,the traditional electrical system can't meet the modern large-capacity,high-speed,high-accuracy information transmission requirements,so microwave photonics came into being(Microwave photonics: MWP),which is sent by optical a comprehensive discipline dealing with electrical signals.Stimulated Brillouin Scattering(SBS),as a nonlinear optical effect,is widely used in optical filtering systems because it can generate gain peaks at specific frequencies.With the rise of modern all-optical communication,integration Microwave systems have received more and more attention.It has become a trend to develop optical waveguides that can replace optical fibers.Integrated microwave photonic filters have also received more and more attention as an integrated optical device.This paper introduces the development of microwave photonics and the basic theory of SBS,and analyzes and designs the integrated microwave photonic filter based on SBS.Firstly,various common integrated waveguide materials are analyzed from material nonlinearity,integration degree and fabrication process.These analyses are based on SBS,mainly based on the addition of various materials to SBS gain.The analysis finally determines the core material of arsenic sulfide as the waveguide,and then combines the light field limitation,the sound field limitation and the acousto-optic coupling efficiency analysis to propose a semi-suspended waveguide structure.The cross section of the core layer is 0.9?m and the length is 3.9cm.The support material is silicon dioxide,and the contact width of the support with the core layer is 0.2 ?m,in which case the SBS gain is 54 dB and the 3 dB line width is 8.2 MHz.Then the effect of the slow light retardation effect of the Bragg grating on the energy of the light field is analyzed.By strictly calculating the period of the Bragg grating and the modulation depth,the enhanced light wave frequency falls just at the SBS gain peak of the arsenic sulfide.It is 344.67 nm and the modulation depth is 10^(-4),which further enhances SBS.At the same time,the SBS line width is further reduced due to the inverse relationship between SBS gain and line width.The final gain is 58.5dB and the 3dB line width is 7.8.At MHz,the waveguide has a section length of 0.9 ?m,a length of 3.9 cm,and a pump optical power of 248 mW,which greatly improves the SBS filtering performance,waveguide integration,and energy utilization.