Integrated Fiber Ring Laser Temperature Sensor Based on Vernier Effect with Lyot-Sagnac Interferometer.

Area of Science:

• Optical Engineering
• Fiber Optic Sensors
• Laser Physics

Background:

• Traditional optical fiber sensors often suffer from low signal-to-noise ratios and broad bandwidths.
• Existing Sagnac loop systems for sensing can be complex and less sensitive.
• The Vernier effect offers a potential mechanism for amplifying sensor signals.

Purpose of the Study:

• To develop an ultra-high sensitivity temperature sensor.
• To investigate the application of the Vernier effect in a Lyot-Sagnac loop for enhanced temperature sensing.
• To improve signal-to-noise ratio and bandwidth in fiber optic temperature sensors.

Main Methods:

• Incorporation of a Lyot-Sagnac loop into a ring laser cavity.
• Fusion of the Sagnac loop by adjusting the welding angle between two polarization-maintaining fibers (PMFs).
• Experimental and theoretical analysis of sensor performance under varying temperatures.

Main Results:

• Achieved a temperature sensitivity of 2.391 nm/°C, an eight-fold increase compared to a single Sagnac loop (0.298 nm/°C).
• Demonstrated the Vernier amplification effect via PMF rotating shaft welding.
• Obtained superior signal-to-noise ratios (up to 50 dB) and narrow bandwidths (<0.2 nm) using the Sagnac loop as a filter within a fiber ring laser (FRL).

Conclusions:

• The proposed sensor exhibits a simple structure and ultra-high sensitivity.
• The Vernier effect in a fused Lyot-Sagnac loop significantly enhances temperature sensing capabilities.
• This sensor shows promise for applications such as biological cell activity monitoring.