Terminated optical fiber sensor based on surface plasmon resonance for refractive index detection

A novel refractive index sensor has been presented which is characterized by the sensing part on the tip of the optical fiber. The principle of this sensor is based on surface plasmon resonance at the interface between gold and medium to be detected. In order to induce the evanescent wave interrogation, the proposed structure has been devised to deliberately leak the transmitted light into the cladding layer of the fiber by a mechanical cleaving and a thermal fusion splicing. The sensor response obtained from the spectral experiment exhibited availability in the use of spectral and optical intensity operation. The sensitivity for the case of spectral operation has achieved the values of 3.35*10(-4) and 4.99*10(-5) for 1.333 and 1.398 refractive index units, respectively.