In　recent　years,　lithium　niobate　(LiNbO3)　has　been　widely　used　in　optical　fiber　communication,　quantum　communication,　fiber　optic　gyroscopes　and　microwave　photonics　as　an　important　photonic　material.　Lithium　niobate　on　insulator　(LNOI)　has　attracted　much　attention　as　an　emerging　photonic　integrated　material.　Compared　with　traditional　lithium　niobate　crystal　materials,　LNOI　materials　have　the　ability　to　realize　miniaturized　photonic　devices　with　higher　efficiency　and　lower　energy　consumption,　thus　showing　great　potential　in　the　design　and　manufacture　of　photonic　devices.　However,　due　to　the　high　hardness　and　inactive　chemical　properties　of　LNOI　materials,　the　traditional　semiconductor　process　cannot　process　its　nanostructures,　which　limits　the　optimization　of　the　key　performance　indicators　of　the　device,　thus　hindering　the　further　development　of　high-quality　and　miniaturized　LNOI　optoelectronic　functional　devices.　In　the　preparation　process　of　the　LNOI　waveguide,　the　sidewall　of　the　ridge　waveguide　formed　by　etching　is　often　not　flat　enough,　which　may　lead　to　an　increase　in　light　scattering　loss.　To　solve　this　problem,　surface　polishing　technology,　especially　chemical　mechanical　polishing　(CMP),　has　become　an　important　method.　Polishing　the　surface　of　the　LNOI　device　by　CMP　can　reduce　the　roughness　of　the　waveguide　sidewall　after　etching,　improve　the　performance　and　power　transmission　efficiency　of　the　device,　and　ensure　that　the　sidewall　surface　is　flat　and　smooth　to　achieve　the　minimum　optical　coupling　loss　and　maximum　power　transmission.　©　COPYRIGHT　SPIE.　Downloading　of　the　abstract　is　permitted　for　personal　use　only.