Microbubble-based optical fiber Fabry-Perot sensor for simultaneous high-pressure and high-temperature sensing.

Area of Science:

• Optical Engineering
• Materials Science
• Sensor Technology

Background:

• Fabry-Perot interferometers (FPIs) are crucial for various sensing applications.
• Existing FPI sensors often face limitations in harsh environments, particularly with simultaneous pressure and temperature measurements.
• Microbubble-based structures offer unique optical properties for sensor development.

Purpose of the Study:

• To propose and demonstrate an all-silica Fabry-Perot interferometer (FPI) sensor based on a microbubble.
• To enable simultaneous high-pressure and high-temperature measurements in challenging environments.
• To evaluate the sensor's sensitivity and cross-sensitivity characteristics.

Main Methods:

• Fabrication of a microbubble-based air cavity using a hollow silica tube and a single-mode optical fiber.
• Utilizing the silica cavity's thickness for temperature sensing and the microbubble structure for pressure sensing.
• Analyzing the reflection spectrum shifts in response to applied pressure and temperature variations.

Main Results:

• Demonstrated a linear wavelength shift versus pressure with a sensitivity of -5.083 nm/MPa at room temperature (0–4 MPa).
• Achieved a temperature sensitivity of 12.715 pm/°C within the range of 20–700 °C.
• Observed very low temperature-pressure cross-sensitivity between the two sensing cavities.

Conclusions:

• The proposed all-silica microbubble-based FPI sensor is effective for simultaneous high-pressure and high-temperature measurements.
• The sensor exhibits high sensitivity and minimal cross-sensitivity, making it suitable for harsh environments.
• This technology holds significant potential for advanced monitoring in demanding industrial and scientific applications.