Researching and determination of the strain sensitivity of the fabricated Bragg gratings

This article presents a systematic study of the stretching characteristics of polymer fiber Bragg gratings. Experimental data demonstrate that applying mechanical stretching to polymer fiber Bragg gratings enables a wide tuning range of the Bragg wavelength (over 50 nm) with high reproducibility, reversibility, and repeatability. It was also established that the strain sensitivity of polymer fiber Bragg gratings is 1.46 pm/με, which significantly exceeds the strain sensitivity of silica fiber Bragg gratings. Additionally, it is shown that the relationship between strain and the Bragg wavelength shift exhibits high linearity (correlation coefficient R² = 0.9995), ensuring the reliability of the gratings under mechanical loads. The study confirms the potential of polymer fiber Bragg gratings for use in WDM optical communication systems, fiber optic strain sensors, and medical sensors.