Miniature fiber-optic tip pressure sensor assembled by hydroxide catalysis bonding technology

Area of Science:

• Optoelectronics
• Materials Science
• Biomedical Engineering

Background:

• Traditional pressure sensors face limitations in high-temperature environments and invasive biomedical applications.
• Existing fiber-optic sensors may lack the robustness required for sterilization or extreme conditions.

Purpose of the Study:

• To develop and demonstrate a miniature fiber-optic tip Fabry-Perot (FP) pressure sensor with enhanced high-temperature survivability.
• To utilize hydroxide catalysis bonding (HCB) technology for robust and precise assembly of the sensor.
• To evaluate the sensor's performance for biomedical pressure diagnostics and harsh environment monitoring.

Main Methods:

• Fabrication of a fiber-optic FP sensor by fusion splicing a single-mode fiber to a fused silica hollow tube.
• Bonding of an ultrathin silicon diaphragm (from SOI wafer via MEMS) to the hollow tube using HCB technology.
• Characterization of the sensor's static pressure and temperature response, including sensitivity and temperature dependence.

Main Results:

• The sensor operates within a 0–100 kPa pressure range, suitable for biological blood pressure measurement.
• Achieved a pressure sensitivity of 2.13 nm/kPa with a resolution of 0.32%.
• Demonstrated exceptional high-temperature resistance up to 600°C and low temperature dependence (0.09 kPa/°C).

Conclusions:

• The HCB-assembled fiber-optic FP pressure sensor offers excellent high-temperature survivability and precise measurement capabilities.
• The polymer-free bonding and silicon diaphragm contribute to the sensor's robustness and low temperature sensitivity.
• The sensor is well-suited for invasive biomedical pressure diagnostics and monitoring in demanding environments.