We have analyzed and compared the spectral differential phase sensing performance for conventional and long-range
(LR) surface plasmon resonance (SPR) across a wide sample refractive index range (i.e. dynamic range) of 1.3330-
1.3505 using Fresnel's Equations and Transfer Matrix method. We demonstrate that wide-range detection limit as high
as 7.9×10<sup>-9</sup> RIU (Refractive Index Unit) for conventional SPR can be achieved with a set of optimized sensing
parameters and a phase measurement resolution of 2×10<sup>-4</sup> rad, whereas best detection limit for LRSPR is lower. We
have also investigated for the effect of sensing parameters including angle of incidence, metal film material and
thickness. LRSPR is found to be quite tolerant to the choice of material and thickness of metal film. This work presents a
comprehensive comparison between conventional and LR SPR for spectral-phase configuration.