[OPTICAL REVIEW Vol. 21, No. 2 (2014) 143-149]
© 2014 The Japan Society of Applied Physics

Numerical Analysis of GeO2-Concentration Effects in Arc-Induced Long-Period Fiber Gratings under External Refractive-Index Changes

Valentin GUZMAN-RAMOS, Daniel E. CEBALLOS-HERRERA*, and Romeo SELVAS-AGUILAR

Universidad Autónoma de Nuevo León, Facultad de Ciencias Físico Matemáticas, Av. Universidad S/N, Cd. Universitaria, San Nicolás de los Garza, Nuevo León, México

(Received November 14, 2013; Revised January 19, 2014; Accepted February 4, 2014)

We present a numerical analysis of the response of arc-induced long-period fiber gratings (LPFGs) under ambient refractive-index changes using standard fibers with SiO2 as cladding material and different GeO2 concentration in the SiO2–GeO2 doped core. We obtain that the LPFG-sensitivity is increased using lower GeO2 concentrations and it follows a parabolic behavior. Also, we identify two linear regimes using an external index of 1.37: for GeO2 concentrations between 2 and 3.5 mol %, the LPFG-sensitivity changes with a rate of 3.614 nm per mole fraction of GeO2, while for higher concentrations the sensitivity changes with a rate of 1.39 nm/mol %. Additionally, for fibers with 2 mol % of GeO2, the sensitivity calculated is comparable to this obtained in previous works using corrugated and tapered LPFGs in SMF28 fibers. These results are of interest for the design of improved LPFG-sensors.

Key words: long-period fiber gratings, GeO2 concentration, refractive index measurement

*E-mail address: de.ceballos.herrera@gmail.com

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