Research Of Photoelastic Waveguide Characteristics In Acceleration Seismic Geophone

With the rapid development of the three-component seismic exploration technology,in order to prove complex geological environment, identify oil and gas fields in thereservoirs, and increase the recoverable reserves, the performance of three-componentacceleration seismic geophone that receives the seismic wave signals is vital to thewhole seismic records and the interpretation of seismic data.This task which comes from the national natural science foundation of Chinacombines three-component seismic exploration technology with the theory of integratedoptics, and advances three-component acceleration seismic geophone based on thephotoelastic effect. The structure and working principle of three-component accelerationseismic geophone are indicated based on the structure and working principle ofsingle-component acceleration seismic geophone. The photoelastic effect of LiNbO₃crystal of the substrate of three-component acceleration seismic geophone under theaction of acceleration is analyzed. The symmetric double Y-branch waveguides of dualM-Z interferometer and3dB coupler used for the sharing of optical power are designed.The bending loss of the branch waveguides is analyzed and calculated, and thetransmission of the branch waveguides and the changes of bending loss with length aresimulated. The finite difference beam propagation method is used to set the structureparameters and calculation parameters of3dB coupler and the dual M-Z interferometer,and their optical field transmission is simulated and analyzed. Proton exchange and Tidiffusion technology are compared to explain the principle and process of protonexchange annealing. The branch waveguides in the sensitive component ofthree-component acceleration seismic geophone designed based on the above methodhave the advantages of low loss and good splitting ratio.