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Three-dimensional Optical-resolution Photoacoustic Microscopy
Published on: May 3, 2011
Miniature photonic-crystal hydrophone optimized for ocean acoustics
Onur Kilic1, Michel J F Digonnet, Gordon S Kino
1EL Ginzton Laboratory, Stanford University, 348 Via Pueblo Mall, Stanford, California 94305, USA. okilic@stanford.edu
The Journal of the Acoustical Society of America
|April 12, 2011
Summary
This study presents a novel optical hydrophone, insensitive to hydrostatic pressure, capable of detecting faint ocean acoustic signals. Its design offers high dynamic range and low distortion for underwater acoustic measurements.
Area of Science:
- Photonics and Acoustics
- Fiber-optic sensing technologies
- Underwater acoustic monitoring
Background:
- Traditional hydrophones face limitations with hydrostatic pressure and dynamic range.
- Accurate measurement of low-level ocean acoustic noise is crucial for various applications.
- Existing fiber-optic technologies offer potential for advanced sensor development.
Purpose of the Study:
- To develop a novel optical hydrophone insensitive to hydrostatic pressure.
- To achieve high sensitivity and a wide dynamic range for underwater acoustic measurements.
- To demonstrate a compact, fiber-optic based hydrophone compatible with existing infrastructure.
Main Methods:
- Utilized a Fabry-Perot interferometer with a photonic-crystal reflector interrogated by a single-mode fiber.
- Integrated three sensors with different acoustic power ranges into a sub-wavelength hydrophone head.
- Developed a method to suppress cross-coupling between sensors within the hydrophone head.
Main Results:
- Achieved a sound-pressure-equivalent noise spectral density as low as 12 μPa/Hz(1/2) from 100 Hz to 100 kHz.
- Demonstrated a dynamic range exceeding 160 dB with harmonic distortion below -30 dB.
- Confirmed a wide flatband response over 10 kHz and very low signal distortion.
Conclusions:
- The developed optical hydrophone offers superior performance for underwater acoustic pressure measurements.
- Its insensitivity to hydrostatic pressure and high dynamic range make it suitable for diverse oceanographic applications.
- The compact, fiber-optic design ensures compatibility and potential for widespread adoption in marine sensing.
