The dual-optical-fiber-sensor system proposed in this study
incorporates the FBG-based liquid-level sensor proposed by
Sohn and Shim [8], but the structure design and finite-element
method (FEM) simulation are different. As shown in Fig. 1, the
liquid level sensing makes use of one FBG that is pasted onto
the centric surface of the uniform-strength cantilever beam and a column buoy is used to apply force at the end of the cantilever
beam. The axial strain induces an expansion of the FBG, and
therefore prompts a shift in the FBG wavelength from which
the pressure can then be derived as