An Optical Fiber Infrasound Sensor
Technical rept., 1 Jun 1999-30 Sep 2001
CALIFORNIA UNIV REGENTS LA JOLLA CA SCRIPPS INST OF OCEANOGRAPHY
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We have designed a new type of infrasonic sensor using optical fibers as distributed sensing elements. The design addresses the limitations of the standard pipe filters currently used to average wind-generated, turbulent pressure fluctuations. In addition to maximizing the signal-to-noise ratio, the system has the capability to help estimate signal azimuth and phase velocity. The principal advantage of the Optical Fiber Infrasound Sensor OFIS over the standard pipe filtermicrobaragraph combination is that it measures the integrated pressure variations along its length, not an acoustical sum of the pressure at many points, as is the case for the pipe filter. The OFIS can be made arbitrarily long and deployed in an arbitrary geometry. As its output is the integral of the pressure field along its length, the OFIS is inherently sensitive to signal directivity and can be deployed as a directional array element. We have assembled a prototype optical fiber infrasound sensor, have performed laboratory evaluations, and have run comparisons of the new sensor with more traditional sensors in the field.
- Acoustic Detection and Detectors
- Fiber Optics and Integrated Optics