High Sensitivity Temperature Sensing of Long-Period Fiber Grating for the Ocean

Area of Science:

• Fiber Optic Sensors
• Materials Science
• Environmental Monitoring

Background:

• Long-period fiber gratings (LPFGs) are sensitive to external environmental changes.
• Developing high-sensitivity sensors for ocean temperature monitoring is crucial for marine research and environmental protection.

Purpose of the Study:

• To develop a novel, highly sensitive temperature sensor for oceanographic applications.
• To investigate the performance of a Ge and B co-doped LPFG sensor for temperature detection.

Main Methods:

• Fabrication of a four-layer Ge and B co-doped LPFG.
• Analysis of mode coupling and sensitivity to surrounding refractive index (SRI) and film properties.
• Coating with titanium dioxide (TiO2) and packaging with UV-curable adhesive for temperature sensitization.
• Evaluation of sensor performance under varying temperature conditions and analysis of salt/protein attachment effects.

Main Results:

• The sensor demonstrated a high temperature sensitivity of 3.8 nm/°C within the 5-30 °C range.
• Achieved a resolution of approximately 0.00026 °C, exceeding ordinary sensors by over 20 times.
• Titanium dioxide coating and specific adhesive packaging enhanced sensor performance for ocean temperature detection.

Conclusions:

• The developed Ge and B co-doped LPFG sensor is suitable for accurate ocean temperature measurements.
• The sensor's high sensitivity and resolution meet the requirements for marine monitoring and environmental protection.
• Further analysis of environmental factors like salt and protein attachment provides valuable insights for practical applications.