High-Temperature Fiber-Optic Fabry-Perot Vibration Sensor Based on Single-Crystal Sapphire

Area of Science:

• Optical Engineering
• Materials Science
• Sensor Technology

Background:

• High-temperature environments pose significant challenges for conventional vibration sensors.
• The need for robust sensing solutions in extreme conditions, such as in aerospace and industrial processes, is critical.

Purpose of the Study:

• To propose and characterize a novel fiber-optic Fabry-Perot (F-P) vibration sensor capable of operating at temperatures up to 800 °C.
• To evaluate the sensor's sensitivity, resonant frequency, and nonlinear error across a wide temperature range.

Main Methods:

• Fabrication of the F-P interferometer using ultraviolet-laser ablation and three-layer direct-bonding technology.
• Theoretical calculation of sensor sensitivity and resonant frequency.
• Experimental characterization of sensor performance, including sensitivity, nonlinearity, and axis-dependent response at various temperatures.

Main Results:

• The sensor achieved a sensitivity of 0.876 nm/g at 20 °C, closely matching the theoretical value.
• Nonlinear error was maintained below 0.87% from 20 °C to 800 °C.
• The sensor exhibited significantly higher sensitivity along the z-axis compared to the x and y axes.

Conclusions:

• The developed fiber-optic F-P vibration sensor is suitable for high-temperature applications.
• The sensor demonstrates high sensitivity, low nonlinearity, and directional selectivity.
• This technology holds promise for advanced engineering applications in extreme thermal environments.