A novel hybrid-integrated 3D acceleration geophone, based on Mach-Zehnder interferometer, has been developed. Mach-Zehnder waveguide interferometer based on photoelastic effect of LiNbO3 waveguide was researched and its optimization structure design was accomplished The Mach-Zehnder waveguide interferometer is realized by symmetrical
double Y-branching waveguide and three polarizers, which are monolithically integrated on an X-cut, Y-propagating LiNbO3 substrate. The simulation results performed in FD-BPM agrees with the theoretical analysis wel1. The Mach-Zehnder interferometer is fabricated successfully and the lighting test is proceeding to check the quality of the Mach-Zehnder interferometer Experimental results matches well with the theoretical prediction.
Hybrid-integrated Optical acceleration seismometer and its digital signal processing system are researched and developed. The simple system figure of the seismometer is given. The principle of the seismometer is explicated. The seismometer is composed of a seismic mass,Integrated Optical Chips and a set of Michelson interferometer light path. The Michelson Integrated Optical Chips are critical parts among the sensor elements. The simple figure of the digital signal processing system is given. As an advanced quality digital signal processing (DSP) chip equipped with necessary circuits has been used in its digital signal processing system, a high accurate detection of the acceleration signal has been achieved and the environmental interference signal has been effectively compensated. Test results indicate that the accelerometer has better frequency response well above the resonant frequency, and the output signal is in correspondence with the input signal. The accelerometer also has better frequency response under the resonant frequency. At last, the curve of Seismometer frequency response is given.