In the present work a uniform U–shaped glass rod based fiber optic extrinsic sensor has been develop, to study the content of sugar in sugar solution prepared by adding sugar in equal steps to the water by selecting different lengths of sensing. The U–shaped sensing element is connected between light source operating at wavelength of 660nm and a benchmark power meter at both the ends by using PCS fibers of 200/230μm diameters of both core and cladding respectively. The launched light from the source at one end travel through the fibers without any loss and with a substantial loss at the region of sensing, due to evanescent wave absorption and reaches detector at the other end. The amount of loss at the sensing zone depends upon the concentration of liquid, which becomes the guiding medium at the region of sensing, the length of sensing region and also wavelength of the operating light. To estimate the sugar concentration, different amounts of sugar has been added to the water and different sensing lengths have been selected and at each case the amount of power reaching the detector and the concentration of liquid in terms of refractive index have been noted and hence a calibration curve is plotted which can be used to measure the unknown concentration of sugar in the solution of sugar.
Volume 11 | 10-Special Issue