Static pressure sensitivity amplification in interferometric fiber-optic hydrophones.

Area of Science:

• Optics
• Materials Science
• Acoustics

Background:

• Interferometric fiber optic hydrophones are crucial for underwater acoustic sensing.
• Understanding the mechanical response of these hydrophones to static pressure is essential for accurate performance prediction.
• Existing models may not fully capture the complex stress distribution within jacketed fibers.

Purpose of the Study:

• To investigate the optical phase change in a single-mode fiber optic hydrophone under static pressure.
• To compare the predictions of hydrostatic and radial mechanical models for this phenomenon.
• To evaluate the influence of fiber jacket materials on hydrophone sensitivity.

Main Methods:

• Utilized 3-D elastostatic solutions for multilayered cylinders to model mechanical behavior.
• Calculated induced optical phase changes using both hydrostatic and radial models.
• Varied parameters such as jacket diameter and elastic properties in the calculations.

Main Results:

• The 3-D models' predictions can be simplified using 2-D plane strain models.
• Fiber optic hydrophone sensitivity is enhanced by the presence of a jacket compared to a bare fiber.
• The radial model predicted a greater sensitivity amplification than the hydrostatic model.

Conclusions:

• Both 3-D and simplified 2-D models provide valuable insights into hydrophone behavior under pressure.
• Jacketed fibers offer improved sensitivity for interferometric fiber optic hydrophones.
• The hydrostatic model's predictions align well with experimental static pressure sensitivity measurements.