Simultaneous measurement of refractive index and temperature using a double antiresonant hollow core fiber

Marta S. Ferreira, Jörg Bierlich, Jens Kobelke, Joao Pinto, Katrin Wondraczek, Manuel Filipe P. Martins Costa
2019 Fourth International Conference on Applications of Optics and Photonics  
In this work, an inline sensor based on a double antiresonant hollow core fiber is proposed for the simultaneous measurement of refractive index and temperature. The fiber, consisting of four silica capillaries with wall thickness of ~1.5 m and a cladding with a thickness of ~36.5 m, is spliced between two sections of single mode fiber. The spectral behavior, measured in transmission, results from the combination of different frequencies which enable the discrimination between the two
more » ... rs. The sensing head is subjected to refractive index measurements using aqueous solutions with different concentrations of ethanol. For a sensor with a length of ~10 mm, and considering the lower frequency signal, the sensitivity to refractive index is 389.6 nm/RIU, whereas for the higher frequency, the sensitivity attained is 2.8 nm/RIU. On the other hand, the sensing head presented a sensitivity to temperature of 25.5 pm/K and -27.6 pm/K for the higher and lower frequencies, respectively.
doi:10.1117/12.2527473 fatcat:u7plw3qx7ncanp3zohxtumsy24