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Sensitivity Improvement of a Humidity Sensor Based on Silica Nanospheres on a Long-Period Fiber Grating
-Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal
INESC Porto, Rua Dr. Roberto Frias, 378, 4200-465 Porto, Portugal
Universidad Pública de Navarra, Campus Arrosadia, 31006 Pamplona, Spain
* Author to whom correspondence should be addressed.
Received: 29 October 2008; in revised form: 19 December 2008 / Accepted: 15 January 2009 / Published: 16 January 2009
Abstract: This work addresses a new configuration that improves the sensitivity of a humidity sensor based on a long-period fiber grating coated with a SiO2-nanospheres film. An intermediate higher refractive index overlay, deposited through Electrostatic Self-Assembly, is placed between the fiber cladding and the humidity sensitive film in order to increase the total effective refractive index of the coating. With this intermediate design, a three-fold improvement in the sensitivity was obtained. Wavelength shifts up to 15 nm against 5 nm were achieved in a humidity range from 20% to 80%.
Keywords: Humidity sensor; long-period fiber grating; nanospheres; electrostatic self-assembly
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Viegas, D.; Goicoechea, J.; Santos, J.L.; Araújo, F.M.; Ferreira, L.A.; Arregui, F.J.; Matias, I.R. Sensitivity Improvement of a Humidity Sensor Based on Silica Nanospheres on a Long-Period Fiber Grating. Sensors 2009, 9, 519-527.
Viegas D, Goicoechea J, Santos JL, Araújo FM, Ferreira LA, Arregui FJ, Matias IR. Sensitivity Improvement of a Humidity Sensor Based on Silica Nanospheres on a Long-Period Fiber Grating. Sensors. 2009; 9(1):519-527.
Viegas, Diana; Goicoechea, Javier; Santos, José Luís; Araújo, Francisco Moita; Ferreira, Luís Alberto; Arregui, Francisco J.; Matias, Ignacio R. 2009. "Sensitivity Improvement of a Humidity Sensor Based on Silica Nanospheres on a Long-Period Fiber Grating." Sensors 9, no. 1: 519-527.