Sistemas de sensores ópticos baseados em fibra óptica de perfil-W dopada com Érbio / Optical sensing systems based on Erbium-doped W-fiber

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

30/07/2012

RESUMO

Depressed-cladding (often referred to as dual-clad or "W"- fiber) fibers with fundamental-mode cutoffs provide high distributed losses at long wavelengths and low losses at short wavelengths. The magnitude of the abrupt transition between low-loss at short wavelengths and high-loss at long wavelengths exceeds 200 dB/km and is found to be extremely sensitive to fiber curvature. The phenomenon is attributed to mode coupling between the core-guided mode and the discrete modes guided in the outer cladding. The active depressed-cladding Er: Al/Ge/SiO2 fiber (DC ? EDF) may be designed to have a fundamental mode cutoff near 1530 nm and provides distributed suppression of C-band amplified spontaneous emission (ASE) to the advantage of that in the S-band. This phenomenon, associated with the mechanism of induced bending loss, provides an alternative approach to obtain amplification in S-band, required to expand the capacity of wavelength-division multiplexing (WDM) systems. A S-band depressed-cladding erbium-doped fiber ring laser which can be tuned through the active fiber bending losses or by using an optical tunable filter, can be designed as well. Due to the amplification and lasing characteristics developed for S-band, based on unique properties, the DC - EDF was the basis of the optical sensing systems developed in this work. In fact, the sensing systems proposed showed high sensitivity, high dynamic range and wide bandwidth, and can be used to monitor static parameters, such as force, pressure, displacement and dynamic parameters used in acoustics and vibrations. Two types of sensing systems, with different approaches, have been studied: an amplifier-sensor and a laser-sensor. The performances of these sensing systems in S-band (1490 and 1510 nm) were studied and analyzed in static and dynamic conditions.

ASSUNTO(S)

sensor optico amplificadores a fibra dopada com erbio fibras óticas lasers de terras raras sistemas wdm optical sensor erbium-doped fiber amplifiers fiber optics rare earth lasers wdm systems

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