A Novel Optical Waveguide Based Accelerometer
F. Chen, Z. Salcic and J. Wang
The University of Auckland, NZ
accelerometer, sensor, optical, micomechanical
A novel accelerometer proposed in this paper utilizes desired advantages which waveguide structure has as its sensor, such as high sensitivity due to photoelastic effect and wide spectral response range. It extends previous research by combining optical sensor with micromechanical part, which converts the acceleration into light phase change, and electronic part, which converts the light phase variations that contain the acceleration information into electrical analog signal. This signal is further converted into digital form in order to perform its demodulation and calculation of measured acceleration. The optical sensor structure is a modified Mach-Zehnder Interferometer (MZI), which has two branches placed on a proof mass. One branch is used as a sensing waveguide and the other as a reference waveguide. The diaphragm structure is placed under the sensing arm, which senses the incoming acceleration based on the photoelastic effect. The reference signal in reference arm is introduced by electro-optical modulation. The electrodes are applied on the reference arm to modulate the phase of the light signal. The intensity of the output signal from the MZI structure contains the phase variation information caused in both sensing arm and reference arm. The output light passes the Bragg Grating which acts as an optical filter. The optical signal is then converted into electrical form by a photo detector for further processing.
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Nanotech 2006 Conference Program Abstract