The Key Technology Research Of High Q Value And Centimetre-level Plane Microcavity Used In The Resonant Gyroscope

Integrated miniature optical waveguide resonant gyroscope is based on the principle ofresonant gyroscope and using MEMS technology to fabricate the small volume and massoptical gyro in chip level. It not only can greatly reduce the volume and weight, but also cansufficiently reduce the heating effect of the device. This is an important direction of thedevelopment of the gyro. As the resonant is the core sensitive unit of the gyroscope, theselection of the cavity is very importannt in the study of gyro. The traditional optical fiberring resonator is difficult to realize the integrated production of chip level, which can not beapplied to integrated micro gyroscope. Doped silica waveguide ring resonator and lithiumniobate waveguide cavity which are used in integrated optical waveguide gyroscope due tothe low Q value, causing that the sensitivity of the gyro is not high. To solve these problems,this article selects with silicon-based silica wedge cavity as the core of integrated micro gyrosensitive unit, and the method of the production process is explored.In this paper, the analysis of principle of resonant gyroscope and limited resolutiondetermined by photoelectric detector gyro are made，which drawing a conclusion that toimprove the Q value of the resonator and the cavity diameter of product is the key to improvegyroscope sensitivity; Silicon dioxide wedge cavity has a very high Q value potential, notonly can realize mass production through MEMS technology, but also has the possibility toachieve larger size, that is very suitable for integrated miniature optical waveguide gyroscope.Through a lot of technology exploration of practice, a set of the wet etching processscheme for the fabrication of wedge cavity is summed up, process parameters was introducedin detail in the process of the selected process and the details should be paid attention to in theprocess; Many problems in the process are analyzed, and the causes and solutions are alsointroduced. Then the paper summarizes the corrosion wedge Angle and the relationship of the mask layer used based on a large number of experimental basis, it is concluded that the biggerthickness of the same photoresist, the larger wedge Angle etched, and the higher steep degreeof different photoresist edge topography, the greater the wedge angle.In order to test the feasibility of that process method, we built the wedge cavityresonance performance testing system and complete the coupling experiment. The test resultsshow that the Q value is2×106of the1.5cm-diameter resonator,when it’s used in gyrosystem, the extreme sensitivity could be achieved to3°/h.In addition, the article also introduces the principle of resonant cavity in detail, theinfluence of coupling coefficient and the cavity length on the Q value has been made by thetheoretical analysis and experimental verification.