Static phase change in a fiber optic coil hydrophone

Area of Science:

• Acousto-optic interactions
• Fiber optic sensing
• Hydrophone technology

Background:

• Modeling acousto-optic interaction in fiber optic interferometric coil hydrophones at low frequencies relies on hydrostatic and radial stress assumptions.
• An ambiguity exists in selecting the appropriate stress model for these hydrophones.

Purpose of the Study:

• To experimentally determine the correct model for acousto-optic interaction in fiber optic interferometric coil hydrophones.
• To resolve the ambiguity between hydrostatic and radial stress models.

Main Methods:

• Utilized a phase modulator with an optical fiber bonded to a piezoelectric PVF(2) film.
• Performed unambiguous experimental determination of the sign of the induced static phase change.

Main Results:

• The experimental results unequivocally demonstrated that the hydrostatic model is the only valid model.
• The radial stress model was shown to be inappropriate for low-frequency acoustic sensing.

Conclusions:

• The hydrostatic model accurately describes acousto-optic interaction in fiber optic interferometric coil hydrophones at low frequencies.
• Experimental validation is crucial for resolving ambiguities in sensor modeling and ensuring accurate performance.