Characteristics of Sensor Response of a Difference Interferometric Slab Optical Waveguide Refractive Index Sensor with a Prism Coupling Method

Abstract

We developed a difference interferometric slab optical waveguide (SOWG) refractive index (RI) sensor for flow analysis which used a prism coupling method. The highest sensitivity of 7.2×10^-7 (ΔRI unit) was obtained with a glass SOWG fabricated with a radio frequency sputtering method for solution samples such as sucrose solutions and mixtures of ethanol and water; here sensitivity was defined as the ΔRI which gives the signal intensity of 10-4 in absorbance unit. The sensitivity is almost the same level as that of a surface plasmon resonance sensor.