Fabrication And Optical Properties Of All-solid-state Micro-quartz Glass Fabry-p(?)rot Cavity

Sensors based on fiber optic Fabry-Pérot(F-P)cavities have the advantages of antielectromagnetic interference,easy miniaturization,high sensitivity,high temperature resistance,and low cost,so they are widely used in aerospace,large-scale component monitoring,oil production,medical treatment,etc.an area.At present,the mature optical fiber F-P cavity is mainly based on moving parts such as membranes.The membrane vibrates under the interference of the external environment,resulting in the change of the interference signal.External information can be obtained by detecting this deformation.The thinner the membrane is,the higher the sensitivity is,but the thinner membrane is easier to break with a strong external environment.Therefore,the membrane-based F-P sensor cannot achieve high sensitivity and a large dynamic range simultaneously.In this paper,based on Microelectromechanical Systems(MEMS)technology,a compact optical fiber F-P cavity that can be used for high temperature sensing is designed in the future.It has the potential to achieve both high sensitivity and large dynamic range in the future The interference principle and direct bonding principle of the F-P cavity are analyzed.The advantages of quartz glass material for manufacturing high temperature resistant F-P cavity are expounded.Micro F-P cavity with high consistency and mass production is designed and processed.Scanning electron microscope is used for observation and precision load testing machine is used for tensile strength test.It is verified that the bonding strength of the F-P cavity is excellent.The optical properties of the fabricated F-P cavity are also studied.This paper studies the following four aspects:(1)The theoretical basis of Far-Perspective cavity interference is described in detail,and the theory of spontaneous pre-bonding at room temperature and the factors affecting bonding are described and its solution is proposed.And from the aspects of chemical properties,mechanical properties,thermal properties and optical properties,it is considered whether quartz glass is a relatively ideal material when making optical fiber Faber high temperature sensitive components.Based on this,the overall structure of an all-solid-state compact fiber F-P cavity is designed,and the problem that the cavity length is difficult to precisely control is solved.(2)The design of the process flow and the preparation of the device were carried out for the designed all-solid-state F-P cavity.The process includes wafer preparation,cleaning,plasma treatment,pre-bonding,direct bonding,magnetron sputtering,dicing,packaging and other steps.After the direct bonding of the quartz glass sheet,the reticle drawn by the L-Edit software is used to realize the magnetron sputtering of the scribe line,and the dicing is carried out.The silica optical fiber was vertically inserted into the sandwich structure by the aid of the silica glass ferrule to complete the fabrication of the compact F-P cavity.(3)The microstructure was observed by scanning electron microscope and elemental analysis was performed by energy dispersive spectrometer to test the bonding condition,and it was verified that the all-solid-state F-P cavity could be mass-produced.The bonding strength of the sandwich structure is tested by the tensile force,and the bonding strength far exceeds the minimum bonding strength value recommended in the manufacture of semiconductor MEMS devices,which verifies the high consistency of the fabricated F-P cavity.(4)The spatial optical coupling test is performed on the sandwich structure,glass ferrule and optical fiber that are not packaged,and a comparison experiment is conducted with the optical fiber coupling test of the F-P cavity after the package.Performance interference is minimal.The Q value of the F-P cavity is 2711.