A diaphragm-free fiber Fabry-Perot gas pressure sensor

Area of Science:

• Optoelectronics and Photonics
• Fiber Optic Sensing Technology
• Gas Pressure Metrology

Background:

• Traditional gas pressure sensors often rely on diaphragms, which can be fragile and limit performance.
• Extrinsic Fabry-Perot interferometers (EFPI) offer a promising platform for developing robust and sensitive optical sensors.
• Accurate gas pressure monitoring is crucial in various industrial and scientific applications.

Purpose of the Study:

• To propose and experimentally demonstrate a diaphragm-free fiber optic gas pressure sensor.
• To investigate the sensor's performance, including sensitivity and response under varying conditions.
• To leverage the refractive index change of gas with pressure for sensing.

Main Methods:

• Fabrication of the sensor using a sandwich structure of single mode fiber, hollow core fiber (HCF), and coreless fiber.
• Creation of a gas-permeable micro-channel in the HCF using a femtosecond laser.
• Utilizing the extrinsic Fabry-Perot interferometer principle to detect pressure-induced changes in optical path difference.

Main Results:

• Achieved a high gas pressure sensitivity of approximately 1.80 µm/MPa within the range of vacuum to 10 MPa at room temperature.
• Demonstrated the sensor's functionality and response characteristics under elevated temperatures.
• Confirmed the linear relationship between gas pressure and the refractive index of the gas.

Conclusions:

• The developed diaphragm-free EFPI sensor offers a robust and miniature solution for gas pressure sensing.
• The sensor exhibits excellent sensitivity and a large measuring range, suitable for demanding applications.
• This technology presents a viable alternative to conventional diaphragm-based pressure sensors.