Fiber optic sensor reduced by chemical etching for measuring refractive index of sucrose solutions

In the present work, the reduction of single-mode optical fibers by chemical etching and its application as evanescent wave sensor for sucrose solutions was studied. The cladding of an optical fiber was completely removed... [ view full abstract ]

In the present work, the reduction of single-mode optical fibers by chemical etching and its application as evanescent wave sensor for sucrose solutions was studied. The cladding of an optical fiber was completely removed using hydrofluoric acid at a concentration of 48-51% (obtaining a
rate of etching of ~3.27 μm/min) in order to leave the core uncovered. Using an infrared continuous wave radiation source at 1550 nm and an
optical fiber with a reduced diameter of ~500 nm, it was possible to
characterize sucrose solutions at different concentrations [0% (water)
to 65%] and their respective refractive refractive indices [n=1.31 to n=1.44, respectively]. The results obtained in this work suggest that the etched optical fiber
could be used as a liquid refractive index sensor, which may plays an
important role in chemical applications. Furthermore, this sensing
device shows potential application to measure glucose levels in blood.