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A simple D-shaped photonic crystal fiber (PCF)based surface plasmon resonance (SPR) biosensor is proposed for refractive index sensing in visible to near infrared (IR) region. A thin Titanium di-oxide (TiO ₂ ) layer is used as an adhesive layer to strongly attach the plasmonic gold (Au) layer with silica fiber surface. TiO ₂ also helps to tune the operating sensor wavelength from visible to near IR (550-1770-nm wavelength). Finite-element method has been used to investigate the guiding properties. The proposed sensor shows the maximum wavelength interrogation sensitivity of 46 000 nm/RIU and the average sensitivity of 9,800 nm/RIU in the sensing range of 1.33-1.43. It also shows the maximum amplitude sensitivity of 1,086 RIU ^-1 . Using the wavelength and amplitude interrogation methods, proposed sensor gives the theoretical maximum resolution of 2.2 × 10 ^-6 and 9.2 ×10 ^-6 RIU, respectively. To the best of …