Improved performance of a fiber-optic hydrogen sensor based on a controllable optical heating technology

Area of Science:

• Materials Science
• Optical Engineering
• Chemical Sensing

Background:

• Accurate hydrogen detection is crucial for safety and industrial processes.
• Existing sensors face challenges in response time, detection limits, and stability.
• Fiber-optic sensors offer advantages in remote and harsh environment monitoring.

Purpose of the Study:

• To propose and experimentally investigate a novel, compact fiber-optic hydrogen sensor.
• To utilize light intensity demodulation and controllable optical heating for enhanced performance.
• To demonstrate the sensor's capabilities in terms of response time, detection limit, and stability.

Main Methods:

• A fiber-optic system employing three photodetectors for signal transformation.
• A WO3-Pd2Pt-Pt composite film deposited on single-mode fiber for hydrogen interaction.
• A 980 nm laser and PID controller for maintaining an optimal operating temperature (60°C).
• Utilizing amplified spontaneous emission (ASE) light source and short fiber Bragg grating (SFBG) for signal demodulation.

Main Results:

• The sensor achieved a rapid response time of 0.4 s for 10,000 ppm hydrogen in air.
• A low detection limit of 5 ppm hydrogen in air was demonstrated.
• Controllable optical heating significantly enhanced sensor stability.

Conclusions:

• The developed fiber-optic hydrogen sensor is compact, efficient, and stable.
• The combination of light intensity demodulation and optical heating offers a promising approach for hydrogen sensing.
• This technology has significant potential for various applications requiring sensitive hydrogen detection.