Abstract
In this paper, we briefly introduce surface-plasmon resonance (SPR) sensor for refractive index measurement using different types of optical fi bers. We focus on an SPR sensor proposed by us based on a Bragg fi ber structure. In this geometry, an HE11-like Bragg fi ber core mode is designed to excite the surface plasmonic wave. It is shown that reduction of core size enables measurement of refractive index signifi cantly lower than that of the silica core. This makes the device useful for biosensing or chemical sensing applications handling aqueous samples. The proposed sensor is fabricated using a sputtering method, and SPR-induced extinction of more than 20 dB is observed.
