Reasearch On Magneto-opitic Film With Large Faraday And Low Loss And Its Application In Magneto-optic Switch

With the development of optical fiber communication technology and the Internet,the development of all-optical networks has emerged in response to the needs of the times.All-optical switching is the core technology of all-optical networks.As the basic unit of optical switching system,optical switch has become the research focus of scientific researchers.Compared with other optical switches,magneto-optical switches made based on the magneto-optical effect have the advantages of fast speed,high stability,low driving voltage and small crosstalk.The development of science and technology puts forward new requirements for devices and materials.It has become the goal of people to study magneto-optical materials to improve the Faraday effect of materials and reduce optical loss as much as possible.In the near-infrared range,rare earth garnet crystals represented by yttrium iron garnet(Y3Fe5O12,YIG)have excellent magneto-optical properties and become one of the most promising magneto-optical materials.It is found that doping YIG crystals can improve its magneto-optical properties,especially Bi-doped and Ce-doped YIG exhibits a giant Faraday effect.In this thesis,we prepared magneto-optical films with large Faraday angles and low optical losses.The influence of the process on the properties of magneto-optical films and its application in magneto-optical switches are studied.First,we prepared the(LuBi)3Fe5Oi2 magneto-optical film with the lead-free liquid phase epitaxy process which chosed gadolinium gallium garnet(GGG)as the substrate,and the influence of growth temperature and cosolvent on the structure,composition and performance of the magneto-optical film was analyzed.It is found that the growth temperature will affect the Bi3+content in the film,and the change of the Bi3+content will cause lattice mismatch.The lattice mismatch will produce a large number of defects in the film,which will make the mirror effect of the sample worse,and the defects will affect the incident light.Scattering and reflection will also indirectly weaken the Faraday effect of the material.When the growth temperature is 818?819?,the lattice matching between the magneto-optical film and the substrate is good,the mirror effect of the sample film is the best,the defects in the film are reduced,and the surface roughness is reduced.The Faraday effect of the material is mainly affected by three factors:incident light wavelength,Bi3+content and optical loss caused by defects in the film.Using B2O3 and V2O5 as flux,the growth temperature of 819? is the best process parameter for preparing high-quality magneto-optical film.Finally,using the(LuBi)3FesO12 single crystal film prepared in this paper as the magneto-optical material,a planar magneto-optical switch was designed.