Fabrication and characterization of micro fluidic based fiber optic refractive index sensor

Abstract

A refractive index sensor was proposed by using 3 dimension (3D) grayscale lithography technique. Optical fiber with taper diameter of 12μm was embedded in a closed microfluidic channel. Taper area of optical fiber is in floating condition at the center of micro channel. Grayscale variation range used for this sensor was 70%–74% and thickness variation 430μm–694μm was achieved. The dimension of the sensor was 7.5cm in length and 2cm in width. Fabricated sensor was characterized with air condition and solution concentration from 0.1M to 1M. A sensitivity of 1457nm/RIU is achieved. The measured results show a good repeatability and low temperature cross-sensitivity.