Long-period fiber grating: a specific design for biosensing applications

Area of Science:

• Photonics and Optical Sensing
• Biomedical Engineering
• Materials Science

Background:

• Long-period fiber gratings (LPFGs) are versatile optical fiber sensors.
• Accurate modeling is crucial for optimizing LPFG performance in biosensing applications.
• Understanding add-layer sensitivity is key to reliable LPFG-based measurements.

Purpose of the Study:

• To provide a realistic model for long-period fiber grating (LPFG) sensors in biosensing.
• To quantify the add-layer sensitivity of LPFG sensors.
• To analyze the impact of biological layer thickness and refractive index on LPFG resonant wavelengths.

Main Methods:

• Detailed investigation and modeling of LPFG sensors.
• Quantification of add-layer sensitivity.
• Analysis of LPFG response near mode transition (MT) and turn-around point (TAP).

Main Results:

• The study provides a clear analysis of how biological layer thickness and refractive index affect LPFG resonant wavelengths.
• Add-layer sensitivity was quantified for LPFG sensors.
• Estimated adsorbed layer thicknesses using LPFG wavelength shifts closely matched other measurement techniques.

Conclusions:

• The developed LPFG sensor model offers a more realistic approach for biosensing applications.
• LPFG sensors demonstrate high sensitivity to changes in biological layer properties.
• LPFG-based measurements provide accurate estimations of adsorbed layer thicknesses.