Alterable interferential fineness for high temperature sensing calibration based on Bragg hollow core fiber

Area of Science:

• Optics and Photonics
• Materials Science
• Sensor Technology

Background:

• Accurate high-temperature sensing is crucial for industrial applications.
• Existing calibration methods can be complex or limited in dynamic range.
• Bragg hollow core fiber (BHCF) offers unique optical properties for sensing.

Purpose of the Study:

• To propose and demonstrate a novel method for high-temperature sensing calibration.
• To utilize the alterable interferential fineness in BHCF for dual-function sensing and calibration.
• To validate the sensing structure's performance across a wide temperature range.

Main Methods:

• Fabrication of a sensing structure using BHCF sections of varying lengths.
• Exploitation of anti-resonant reflecting optical waveguide (ARROW) fringes for high-temperature measurement.
• Utilization of short Fabry-Perot (F-P) cavity fringes for temperature calibration.
• Analysis of transmission spectrum to determine temperature sensitivities.

Main Results:

• The ARROW mechanism achieved a temperature sensitivity of 26.03 pm/°C.
• The intrinsic BHCF temperature sensitivity was measured at 1.02 pm/°C.
• A linear response was observed over a wide dynamic temperature range (100 °C to 800 °C).

Conclusions:

• The proposed method offers a novel approach for high-temperature sensing calibration.
• The dual-fringe mechanism provides both measurement and intrinsic calibration.
• The sensing structure demonstrates potential for applications in harsh environments requiring precise temperature monitoring.