Enhanced wavelength tuning of laterally loaded FBG strain sensors through optimization of the pressure transmitting system

Wavelength tuning of fiber Bragg gratings (FBGs) by virtue of a lateral or transverse load is attractive for a variety of applications in the field of optical sensing. The wavelength response characteristic of the FBG upon application of a lateral load is highly dependent on the pressurizing media, its configuration and the contact conditions. In this paper, the effect of stiffness of the pressurizing media, its thickness and the effect of contact friction on the lateral pressure tuning of FBGs is evaluated using finite element method. It is found that significant enhancement in lateral pressure sensitivity and wavelength tuning range is achievable by optimizing these parameters. Also the stress-induced birefringence could be reduced to an insignificant near-zero value. The present study is thus useful in better utilization of lateral pressure tuning of FBGs for sensing applications.