Measurement of CO₂-laser-irradiation-induced Refractive Index Modulation in Single-mode Fiber Toward Long-period Fiber Grating Design and Fabrication
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.
Y. Li et al., "Measurement of CO₂-laser-irradiation-induced Refractive Index Modulation in Single-mode Fiber Toward Long-period Fiber Grating Design and Fabrication," Applied Optics, Optical Society of America, Oct 2008.
The definitive version is available at https://doi.org/10.1364/AO.47.005296
Electrical and Computer Engineering
Keywords and Phrases
Fiber Optics Sensors; Gratings; Fiber optics
Article - Journal
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