We present an effective method to compensate the spatial-frequency nonlinearity for polarized low-coherence
interferometer with location-dependent dispersion element. Through the use of location-dependent dispersive
characteristics, the method establishes the exact relationship between wave number and discrete Fourier transform (DFT)
serial number. The jump errors in traditional absolute phase algorithm are also avoided with nonlinearity compensation.
We carried out experiments with an optical fiber Fabry-Perot (F-P) pressure sensing system to verify the effectiveness.
The demodulated error is less than 0.139kPa in the range of 170kPa when using our nonlinearity compensation process
in the demodulation.
Optical fiber sensor has great advantage for applications dealing with extreme environment. We developed a high
precision optical pressure sensor for aviation industry. The optical pressure sensor is based on two-beam interference of
microcavity and is fabricated with Micro-electromechanical systems (MEMS) and laser fusion technology. The cavity
length variation resulting from external pressure is demodulated with spatial polarization low coherence interference unit
and a high stable phase demodulation algorithm. The effect of light source output parameter is also investigated. We
carried out research on optical fiber strain, temperature and acoustic vibration sensor for aerospace application. The
optical fiber sensors for strain and temperature measurement are based on fiber Bragg grating(FBG).Both bare FBG and
packaged FBG performances under cryogenic temperature and high vacuum are investigated. An eight-channel parallel
FBG wavelength interrogator is developed. The optical fiber acoustic vibration sensor is based on two-beam interference
of microcavity and use intensity demodulation method for high speed response. The mutiple-parameter and multiplepoint
measurement instrument is successfully applied to status monitoring of water sublimator.
We fabricated MEMS-based optical fiber pressure sensor with anodic bonding. The vacuum-sealed microcavity with
a thin silicon diaphragm is used as sensing element and its deformation characteristics determine the pressure
measurement performance. Considering residual gas inside Fabry-Perot cavity and the thermal properties of material, we
established a sensor’s temperature response mathematical model based on ideal gas equation and elastic theory.
Temperature experiment of this sensor was carried out under vacuum. This work will provide a guide of temperature
compensation process for achieving high precision pressure measurement.
A novel demodulation algorithm, comprising of a calibration algorithm and improved linear fitting phase-shift algorithm,
is proposed for optical fiber sensing system based on low-coherence interference. The calibration algorithm is used to
identify the fringe order. Traditional phase-shift algorithm is improved to get the linear fitting curve of the relative phase
corresponding to zero-order fringe and the peak position is retrieved from its zero point. Comparing with Fourier based
algorithms, the computation of proposed algorithm is small (approximately 25 times faster) while sustains high precision
with 2nm maximum error of cavity length. Experiments were carried out to verify the performance.
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