Micro-optical Gyroscope Low-loss Waveguide Design And Manufacturing Process

The key targets of inertia navigation system are high precision and reliability,light weight and miniaturization. Gyroscopes become the emphatically developmental high technology in military and civilian application as key part of inertia navigation system. The integrated optic gyroscopes is the fourth generation gyroscope comparing Mechanical gyroscopes,ring laser gyroscopes and fiber optic gyroscopes, using waveguide to replace fiber and integrating source,splitting,detector, circuit processor and micro-optical accelerometer on the same silicon wafer, then realizing small dimension and reliable operation.The key technology of MOG is the fabrication of low loss waveguide,close curve(RMOG) or spiral curve(IMOG),the groove or ridge waveguide and spatting coating and the fabrication of alternative waveguide using face-face coupling technology, modulating using high efficiency polarization, pick-uping the signal,using accomplished technology of FOG to process digital singnal. So the practically MOG is fabricated.The most important technology of the MOG's fabrication is to fabricate low loss waveguide and form alternative structure using face-face coupling technology,and this will be mostly study in my article by analysing in theory and experimentalizing in practice, the design and coupling method of low loss waveguide are put forward after theoretical analyse, introducing an offset at the junction of two waveguides, etching groove at the outside of bend waveguide and using waveguide lens effect to decrease bend loss. In experiment the photolithography of thick photoresist and reaction ion etching processing are studied for waveguide grooves that have 1:1 ratio of deepth and width, the figure's widen interrelated processings are discussed in theory and experiment, including mask, photoresist, exposal,develop, temperature effect and quadratic effect, The effective minishing techniques are put forward such as spinning more times, minishing buds, baking and etching at low temperature and optical stabilizing. The Reaction Ion Etching Processings are studied for waveguide grooves. Grassy prominence, the key reason for bad figure's roughness, is particulardiscussed. The effective lustrating techniques are also experimentalized in practice, such as photoresist optical stabilizing, inidence angle's adjusting and etching gas pressure alternating. It's beneficial to etching low loss waveguide.Meanwhile, the coupling method, the loss of coupling and its improvement be analysed and studied. Discussing the efficiency for difference coupling method. Introducing the theory of coupling. And one scheme is put forword for system's design.