LED based fiber optic surface plasmon resonance sensor

Modeling of a miniaturized fiber optic sensor based on surface plasmon resonance utilizing a broad band diffuse source is presented. Attenuated total internal reflection with Kretschmann configuration is the basis of the theoretical model. For simulation both meridional and skew rays are considered. The performance of the sensor is evaluated in terms of sensitivity, detection accuracy and signal to noise ratio. Effects of the numerical aperture of the fiber, core diameter and length of the sensing region on the performance parameters of the sensor are studied. The results are obtained for gold and silver metallic layer on the core of the fiber. The theoretical results obtained are compared with SPR based fiber optic sensor utilizing focused beam on the end face of the fiber from a collimated source. The advantages of using broadband LED (diffuse source) source for launching light in the fiber are the miniaturization, compactness and low cost of the sensor.