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A novel electro-optic integrated acceleration seismic geophone is presented in this paper and it is a new kind of
micro-opto-electro-mechanical system (MOEMS). The optical waveguide polarizer, M-Z interferometer, harmonic
oscillator system and waveguide phase modulator are integrated monolithically on silicon substrate with dimensions of
30mm×12mm×0.5mm. Mach-Zehnder waveguide interferometer of Si-based MOEMS acceleration seismic geophone is
researched and its optimization structure design is accomplished. The material of buffer layer and coating layer is K9
glass. Two Bak7 glass Y-branching waveguides with width of 4μm and thickness of 0.4μm, and six guide mirrors are
employed in interferometer. An S-shaped bend is used for the transition connecting two offset parallel waveguides in
Y-branching. Because it is difficulty to make the branching angle large using conventional Y-branching, we designed 90º
directional change by a vertical mirror facet to realize the special structure between measuring arm and reference arm.
The inner dielectric film of the mirror facet is aluminum plating. To prevent polarization state of TE mode polarized light
changed after passing through the aluminum film, 4 polarizers with length of 1mm have been used. The simulation
results performed in BMP agrees with the theoretical analysis well.
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