Long-Period Fiber Grating Sensor Based on a Conductive Polymer Functional Layer

Area of Science:

• Materials Science
• Optical Engineering
• Sensor Technology

Background:

• Long-period fiber gratings (LPFGs) are sensitive to external environmental changes.
• Developing robust and sensitive temperature sensors is crucial for various applications.
• Conductive polymers offer unique properties for functionalizing optical sensors.

Purpose of the Study:

• To fabricate and characterize a novel temperature sensor based on LPFG coated with poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS).
• To evaluate the performance of the PEDOT:PSS coated LPFG sensor for temperature sensing applications.
• To investigate the role of the conductive polymer as a sensing layer and strain buffer.

Main Methods:

• Fabrication of LPFG using laser-assisted wet-chemical etching.
• Coating the LPFG with a functional conductive polymer (PEDOT:PSS).
• Temperature testing of the sensor across three cycles from 30 to 100 °C.
• Measurement of wavelength shift and energy loss as a function of temperature.

Main Results:

• The PEDOT:PSS coating enhanced the grating depth and acted as a strain buffer.
• The sensor exhibited an average wavelength sensitivity of 0.052 nm/°C with 99% linearity.
• Average transmission sensitivity was 0.048 (dB/°C) with 95% linearity.

Conclusions:

• The fabricated PEDOT:PSS coated LPFG sensor demonstrates excellent performance for temperature measurement.
• The conductive polymer coating provides both sensing capability and mechanical enhancement.
• This sensor design offers a promising approach for accurate and reliable temperature monitoring.