Theoretical analysis of tapered fiber optic surface plasmon resonance sensor for voltage sensitivity

•The refractive index sensitivity of SPR sensor with different tip end diameter was studied.•A single wavelength interrogation method is introduced to detect the presence of voltage.•The voltage sensitivity of SPR sensor with different tip end diameter was studied.

The geometry dependent reflecting spectrum, resonance wavelength and sensitivity of surface plasmon resonance (SPR)-based tapered fiber optic sensor have been investigated. It is observed that as the tip end diameter decreases, the refractive index sensitivity of proposed sensor monotonically increases. However, the voltage sensitivity increases with the tip end diameter decreasing to a certain value. The relationship between the tip end diameter and refractive index sensitivity, voltage sensitivity present here gives a guideline to use tapered fiber optic SPR sensor targeting specific applications.