Measurement of CO₂-laser-irradiation-induced Refractive Index Modulation in Single-mode Fiber Toward Long-period Fiber Grating Design and Fabrication

Abstract

We report a new method to measure the CO2-laser-irradiation-induced refractive index modulation in the core of a single-mode optical fiber for the purpose of design and fabrication of long-period fiber gratings (LPFGs) without applying tension. Using an optical fiber Fabry-Perot interferometer, the laser-induced axial refractive index perturbation was measured. We found that the CO2-laser-irradiation-induced refractive index change in the fiber core had a negative value and that the magnitude was a sensitive function of the laser exposure time following almost a linear relation. under the assumption of a Gaussian-shaped refractive index modulation profile and based on the first two terms of Fourier series approximation, the measured refractive index perturbations were used to simulate the LPFG transmission spectra. LPFGs with the same laser exposure parameters were fabricated without applying tension, and their spectra were compared with those obtained by simulations.

Department(s)

Electrical and Computer Engineering

Keywords and Phrases

Fiber Optics Sensors; Gratings; Fiber optics

International Standard Serial Number (ISSN)

1559-128X

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2008 Optical Society of America, All rights reserved.

Publication Date

01 Oct 2008

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