Characteristics of sensor response of a difference interferometric slab optical waveguide refractive index sensor with a prism coupling method

We developed a difference interferometric slab optical waveguide (SOWG) ref ractive index (RI) sensor for flow analysis which used a prism coupling met hod. The highest sensitivity of 7.2x10(-7) (Delta RI unit) was obtained wit h a glass SOWG fabricated with a radio frequency sputtering method for solu tion samples such as sucrose solutions and mixtures of ethanol and water; h ere sensitivity was defined as the Delta RI which gives the signal intensit y of 10(-4) in absorbance unit. The sensitivity is almost the same level as that of a surface plasmon resonance sensor.