Microstructure-FBG hybrid load cell

Abstract

We report the fabrication of an hybrid fibre optic and T-shaped microstructrure inscribed in soda lime microscope slides by using femtosecond laser irradiation technique. that allow to construct true 3-D structures. Within the T-shaped structure a FBG was inserted and glued with photopolymer adhesive. The hybrid structure is sensitive to hydrostatic pressure. Calibration load tests were performed in the range 0 − 100 N.

Lateral force sensing based on fibre Bragg gratings and Gaussian regression process

“…This structure is designed to convert lateral force into axial strain along the fibre. 5 Fig. 1(b) shows the fabrication process of this structure, where glass microscope slides are used and cut using pulses generated by a Ti:Sapphire femtosecond (fs) laser with a central wavelength of 800 nm, and pulses with a repetition rate of 1 kHz, width of 100 fs, and energy of 100 J.…”

“…2 Within the area of sensors, force monitoring is an area of high interest, and therefore, multiple configurations of FBG lateral pressure/force sensors have been reported in the literature. [3][4][5] To use an FBG as a sensor, changes in its peak wavelength (so called Bragg wavelength) caused by the interaction of the optical fiber with the parameter being measured must be detected. A conventional way to detect FBG peak wavelength shifts is using peak tracking methods.…”

“…Indeed, when the grating section is subjected to a transversal force, the FBG spectral response broadens out as a consequence of birefringence-induced effects or due to an uneven force application along the grating. 5,11 These effects can cause the FBG reflection peak to split, 12 making the peak detection a challenging task.…”