Amendment performance of an apodized tilted fiber Bragg grating for a quasi-distributed-based sensor

Area of Science:

• Photonics and Optical Engineering
• Fiber Optic Sensing Technology
• Materials Science for Sensors

Background:

• Reflective-tilted fiber Bragg gratings (R-TFBGs) offer potential for advanced quasi-distributed sensing.
• Optimizing R-TFBG characteristics is crucial for enhancing sensitivity and operational range in temperature-strain sensors.
• Existing sensor systems require improvements in sensitivity and efficiency for extended temperature-strain measurements.

Purpose of the Study:

• To investigate and optimize the reflectivity spectra of R-TFBGs for improved temperature-strain sensing.
• To comparatively analyze the impact of various parameters (core radius, tilt angle, apodization, grating length, index modulation) on R-TFBG performance.
• To evaluate the enhanced performance of R-TFBG quasi-distributed sensors in a practical temperature-strain sensing system.

Main Methods:

• Comparative analysis of R-TFBG performance by varying core radius, tilt angle, and apodization profiles (Kaiser, tanh).
• Optimization of grating length (L) and index modulation amplitude (Δn) to achieve near-unity reflectivity.
• Investigation of R-TFBG characteristics including full width at half-maximum (FWHM), main sidelobe level (MSL), and sidelobe suppression ratio (SLSR).

Main Results:

• Optimal tilt angle and apodization profiles (Kaiser for MSL/SLSR, tanh for decay) were identified.
• Near-unity reflectivity (≈1.0) was achieved by controlling L and Δn.
• An optimized R-TFBG sensor demonstrated upgraded sensitivity for temperature (179°C) and strain (3000 μϵ) at 10° tilt, with specific FWHM, attenuation, MSL, and SLSR values.

Conclusions:

• The study successfully demonstrates optimized R-TFBGs for enhanced quasi-distributed temperature-strain sensing.
• Parameter optimization significantly extends the sensitivity range and efficiency of fiber optic sensors.
• The findings provide a pathway for developing next-generation high-performance fiber optic sensing systems.