Abstract
Problems associated with the demodulation and localization of acoustic signal produced by fiber optic
interferometer are investigated. It is shown that existing demodulation method utilizing 3 × 3 fiber coupler do
not work well for that the acoustic signal cannot reach the full amplitude of the sensor to compensate the dc and
normalize the amplitude. Modifications to improve the performance of the previously proposed demodulation method are
suggested. After the demodulation, two phase difference signals are received to have two signals with fixed time delay
based on a unique data processing method, and hence, the position of the disturbance can be measured by the signal
correlation method to extract the time delay. Operation of the modification of the demodulation method is verified
experimentally along a 20-km-long sensing fiber with the minimum detectable phase signal closed to the noise
equivalent phase (NEP) (0.2 rad). The performance of the sensor is also compared with the conventional sensor, based
on the null frequency of the spectrum of the phase difference generated by the acoustic disturbance. Experimental
results show that the sensor is advantageous for easy installation, low location error, and flexibility for the
application of acoustic localization.
© 2014 IEEE
PDF Article
More Like This
Cited By
You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.
Contact your librarian or system administrator
or
Login to access Optica Member Subscription
Add to BibSonomy