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Passive Fiber Grating Hydrophone Unit Technique Based On Elastic Sheet Sensitization Package Structure

Posted on:2011-09-02Degree:MasterType:Thesis
Country:ChinaCandidate:X F YinFull Text:PDF
GTID:2178330338490077Subject:Optical Engineering
Abstract/Summary:PDF Full Text Request
Aiming at realizing underwater acoustic signal measurement by fiber Bragg grating, the pressure sensitivity, acceleration sensitivity, syntonic frequency and temperature sensitivity of fiber Bragg grating hydrophone based on the package structure of metal elastic sheet are analyzed by the theory of Elastic mechanics. The underwater static pressure sensitivity and temperature compensation of the packaging FBG hydrophone are experimented. The acoustic wavelength-shift sensitivity, acceleration sensitivity and the equivalent noise spectrum level of the FBG hydrophone are tested. The stability and linearity of the FBG hydrophone are analyzed is researched. The simultaneous measurement of the acoustic signal and water depth using the FBG hydrophone is verified by experiment.The main results in the dissertation are as follows:1. The pressure sensitivity, acceleration sensitivity, syntonic frequency and temperature sensitivity of fiber Bragg grating hydrophone are systemically analyzed; Theoretical studies demonstrate shown that this kind of FBG hydrophone has very high pressure sensitivity, low acceleration sensitivity and high fundamental frequency, which particularly adapts to the detection of underwater sound pressure.2. The underwater static pressure sensitivity of the packaging FBG hydrophone is experimented. The results show that the pressure sensitivity of the packaged FBG hydrophone is 33.6nm/MPa, which is 10700 times of the bare fiber grating.3. The acoustic wavelength-shift sensitivity, acceleration sensitivity and the equivalent noise spectrum level of the FBG hydrophone are tested by interference scanning demodulation system. The experiments show that the acoustic sensitivity of FBG hydrophone is -149.5 dB (0dB=1pm/μPa) and the acceleration sensitivity is 501fm/g at 1KHz, meanwhile the frequency response is flat in the range of 80Hz~1600Hz.4. The output stability, linearity and the stability of acoustic sensitivity of the FBG hydrophone are tested. The experiments show that this kind of FBG hydrophone has stable output and highly linearity, the stability of acoustic sensitivity is nice, it can realize the simultaneous measurement of the acoustic signal and water depth as well.
Keywords/Search Tags:fiber Bragg grating, package of enhanced sensitivity, fiber Bragg grating hydrophone, water-depth measurement, water acoustic experiments
PDF Full Text Request
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