Influence of surrounding media refractive index on the thermal and strain sensitivities of long-period gratings

Ricardo Canute Kamikawachi; Gustavo Rafael Collere Possetti; Rosane Falate; Marcia Muller; José Luís Fabris

doi:10.1364/ao.46.002831

Influence of surrounding media refractive index on the thermal and strain sensitivities of long-period gratings

Appl Opt. 2007 May 20;46(15):2831-7. doi: 10.1364/ao.46.002831.

Authors

Ricardo Canute Kamikawachi¹, Gustavo Rafael Collere Possetti, Rosane Falate, Marcia Muller, José Luís Fabris

Affiliation

¹ Federal University of Technology--Paraná, Avenida Sete de Setembro 3165, 80230-901, Curitiba, Brazil.

PMID: 17514227
DOI: 10.1364/ao.46.002831

Abstract

A detailed study of the thermal and strain sensitivities of a long-period grating when the device is immersed in different external media is presented. The range of refractive indices analyzed are within 1.000 to 1.447, corresponding to samples of air, water, ethanol, naphtha, thinner, turpentine, and kerosene. Within the same range of refractive indices, the strain sensitivity is between (-0.24 +/- 0.03) and (-0.94 +/- 0.11) pm/microepsilon. For the grating immersed in these fluids, the refractive index sensitivity ranges from -3 to -1035.6 nm per refractive index units. The coupling thermo-optic coefficients and the strain-optic coefficients are also measured, resulting in the range from (2.45 +/- 0.04)x10(-5) to (15.89 +/- 0.82)x10(-5) deg C(-1) and (-1.15 +/- 0.04) to (-1.61 +/- 0.04) microepsilon(-1), respectively. A noticeable nonlinear behavior of the thermal sensitivity is found for external media with refractive indices higher than 1.430.