Comparison of micro fabricated C and S bend shape SU-8 polymer waveguide of different bending diameters for maximum sensitivity

In this study C and S bend shape SU-8 polymer optical waveguides of different bending diameters have been microfabricated to experimentally investigate the effect of bending on the sensitivity of the waveguides. The real-time change in absorbance with change in refractive index varying from 1.33 to 1.38 of external medium is observed at wavelength 530 nm. It is observed that in both C and S shape, the sensitivity increases with the decreasing bending diameter. After an optimum value any further decrease in bending diameter reduces the sensitivity of waveguides. Maximum sensitivity observed with C shape is 5.35 ΔA / RIU and S shape is 13.04 ΔA / RIU, which is more than twice as compared to C shape.