Single-mode spiral shape fiber based liquid sensor with ultra-high sensitivity and ultra-low loss: Design and analysis

This paper represents a spiral photonic crystal fiber (S-PCF) based optical sensor which exhibits high relative sensitive as well as low confinement loss simultaneously. The proposed PCF contains ten arms as well as each arm consists of nine circular air holes that forms spiral shape and core is formatted with circular holes filled with ethanol. Various geometrical parameters including diameters and pitches of the suggested S-PCF are tuned with the most efficient structure applying the full vectorial finite element method (FEM). Overall outcomes satisfy O + E + S + C + L + U (range of 1.26-1.675 μm) electromagnetic (EM) bands. The relative sensitivities of about 72.95%, 74.55% and 75.14% with ultra-low confinement loss of 1.85 × 10−10 dB/m, 4.62 × 10−11 dB/m and 6.35 × 10−11 dB/m are gained at the 1.33 μm wavelength for water (n = 1.33), ethanol (n = 1.354) and benzene (n = 1.366) analytes respectively. In addition, effective area, non-linear coefficient and V-parameter are also examined. Finally, the inquiry procedure depicts that the proposed S-PCF is highly capable in not only sensing applications but also high data traffic transmission applications.