Design optimisation of C-shaped optical fibre sensor

Abstract

Optical fibre sensors have attracted a lot of interest in the field of sensors. However, the limitation of conventional optical fibre sensors such as high fragility and low sensitivity need to be considered. This work demonstrated a simulation of a new optical sensor design, a C–shaped optical fibre sensor to overcome these limitations. The design optimization of the sensor was conducted by changing the remaining cladding thickness ranging from 5 to 0 µm and opening angle ranging from 70 to 110°. The change in refractive index ranging from 1.30 to 1.40 has been performed to evaluate the simulated sensing performance. The simulation results showed that reducing the cladding thickness and wider opening angle can improve the sensor’s sensitivity. In cladding thickness optimization, the sensor showed the highest sensitivity with no remaining cladding thickness. In the opening angle optimization, the highest sensitivity can be achieved at the maximum opening angle of 110°, but the sensitivity changes due to the the opening angle range were minimal compared to cladding thickness optimization. The best C–shaped sensing performance with 0 µm remaining cladding thickness and 110° opening angle was selected to be compared to the closest in term of design which is the D—shaped optical fibre sensor. Overall, the C–shaped design has more cladding sector region left providing better physical robustness and has high potential to act as a new refractive index sensor with an estimated sensitivity of up to 2.77893, higher than the simulated D–shaped optical fibre sensor with an estimated sensitivity of 2.77468.