  Inspired by the classic theory, we suggest that the performance of a D-shaped
fiber optical surface plasmon resonance (SPR) sensor can be improved by
manipulating the fiber core mode. To demonstrate this, we propose a novel fiber
SPR sensor based on a hollow core photonic crystal fiber with liquid mixture
filled in the core. The fiber sensor design involves a side-polished fiber with
gold film deposited on the polished plane and liquid filling. Numerical
simulation results suggest that by tuning the refractive index of the liquid
mixture, the predicted sensitivity will be over 6,430 nm/refractive index unit
for an aqueous environment, which is competitive for fiber chemical sensing.
This optimization method may lead to an ultrahigh sensitivityfiber optical
biosensor.
