Adaptive Fiber-Ring Lasers Based on Isopropanol Filled Microfiber Coupler for High-Sensitivity Temperature Sensing

Area of Science:

• Optics and Photonics
• Sensing Technology
• Materials Science

Background:

• Traditional fiber ring laser (FRL) temperature sensing systems often require separate filters and sensors.
• Integrating sensing capabilities directly into optical components can simplify system design and reduce costs.

Purpose of the Study:

• To develop a novel, integrated temperature sensing method within a fiber ring laser (FRL) cavity.
• To enhance the sensitivity and efficiency of FRL-based temperature measurements.

Main Methods:

• A micro-fiber coupler (MFC) was designed to function as a beam splitter, filter, and temperature sensor.
• Isopropanol, a liquid with a high photothermal coefficient, was selectively filled into the MFC to amplify temperature sensitivity.
• Temperature measurements were conducted within a dynamic range of 20-40 °C.

Main Results:

• The developed sensor achieved a temperature sensitivity of -1.29 nm/°C with a high linearity (R² = 0.998).
• The sensor exhibited a narrow 3-dB bandwidth (<0.2 nm) and a high signal-to-noise ratio (SNR) (up to 40 dB), characteristic of laser-based sensing.
• The system demonstrated a low cost and high sensitivity.

Conclusions:

• The integrated MFC-based sensor offers a cost-effective and highly sensitive solution for temperature measurement inside FRL cavities.
• This technology holds potential for applications in biomedical health detection and real-time ocean temperature monitoring.