Characterization of nanolayer LPG refractometer according surrounding refractive index
E. Simões, I. Abe, J. Oliveira, J. L. Pinto, University of Aveiro (Portugal); P. Caldas, O. Frazão, INESC Porto - Institute for Systems and Computers Engineering of Porto (Portugal)
In this work the behavior of an optical fiber Long Period Grating (LPG) refractometer with the variations of the surrounding refractive index is discussed. The objective is to characterize optical fiber refractometers sensitive to surrounding refractive index, higher and lower than the cladding. For values of surrounding refractive index higher than the cladding, the LPG does not show enough sensitivity. For this reason, a nanolayer of an organic material was coated onto the fiber, using the Langmuir-Blodgett technique. We characterized LPG covered with different nanolayers thickness (110 and 120 nm) relatively to changes in surrounding refractive index.
