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Fabrication quality analysis of a fiber optic refractive index sensor created by CO2 laser machining.

Chen CH, Yeh BK, Tang JL, Wu WT - Sensors (Basel) (2013)

Bottom Line: Finally, we used the optical fiber sensor fabricated using the improved parameters to measure the refractive indices of various solutions.The results show that a refractive-index resolution of 1.8 × 10(-4) RIU (linear fitting R2 = 0.954) was achieved for sucrose solutions with refractive indices ranging between 1.333 and 1.383.The results provided additional information, specifically, a superior sensor resolution of 5.73 × 10(-5) RIU, and greater linearity at R2 = 0.999.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, National Chung Cheng University, Chiayi 621, Taiwan. saesozj@yahoo.com.tw

ABSTRACT
This study investigates the CO2 laser-stripped partial cladding of silica-based optic fibers with a core diameter of 400 μm, which enables them to sense the refractive index of the surrounding environment. However, inappropriate treatments during the machining process can generate a number of defects in the optic fiber sensors. Therefore, the quality of optic fiber sensors fabricated using CO2 laser machining must be analyzed. The results show that analysis of the fiber core size after machining can provide preliminary defect detection, and qualitative analysis of the optical transmission defects can be used to identify imperfections that are difficult to observe through size analysis. To more precisely and quantitatively detect fabrication defects, we included a tensile test and numerical aperture measurements in this study. After a series of quality inspections, we proposed improvements to the existing CO2 laser machining parameters, namely, a vertical scanning pathway, 4 W of power, and a feed rate of 9.45 cm/s. Using these improved parameters, we created optical fiber sensors with a core diameter of approximately 400 μm, no obvious optical transmission defects, a numerical aperture of 0.52 ± 0.019, a 0.886 Weibull modulus, and a 1.186 Weibull-shaped parameter. Finally, we used the optical fiber sensor fabricated using the improved parameters to measure the refractive indices of various solutions. The results show that a refractive-index resolution of 1.8 × 10(-4) RIU (linear fitting R2 = 0.954) was achieved for sucrose solutions with refractive indices ranging between 1.333 and 1.383. We also adopted the particle plasmon resonance sensing scheme using the fabricated optical fibers. The results provided additional information, specifically, a superior sensor resolution of 5.73 × 10(-5) RIU, and greater linearity at R2 = 0.999.

No MeSH data available.


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Diagram of the components of an optical light transmission defect: (a) laser source; (b) collimator; (c) fiber cable (NA = 0.27); (d) fiber adapter; (e) fiber connecter; and (f) fiber sensor (NA = 0.37).
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f10-sensors-13-04067: Diagram of the components of an optical light transmission defect: (a) laser source; (b) collimator; (c) fiber cable (NA = 0.27); (d) fiber adapter; (e) fiber connecter; and (f) fiber sensor (NA = 0.37).

Mentions: The light transmission defect detection method was primarily based on internal optical fiber core propagation by optically coupling the laser to the process. For this study, we used the structure shown in Figure 10 to guide the laser light inside the optical fiber sensor as it propagates. First, an optical collimator was used to focus the laser source (wavelength: 532 nm; power: 10 mW) inside the optical fiber transmission line (NA = 0.27) during light propagation. At this time, light from the source was transmitted to the end with an NA value of 0.27 and then guided through the optical fiber adapter as it propagated within the optical fiber core (NA = 0.37). The Optical fiber core was then examined to confirm that the confined light source was guided to the core of the optical fiber when propagating. A diagram of the measurement is shown in Figure 11. When the surface is irregular or contains debris from processing, according to the optical transmission principle, irregular surfaces in the path of light transmissions cause the light to diffuse. Observation of the light diffusion phenomenon facilitates the achievement of quality analysis objectives.


Fabrication quality analysis of a fiber optic refractive index sensor created by CO2 laser machining.

Chen CH, Yeh BK, Tang JL, Wu WT - Sensors (Basel) (2013)

Diagram of the components of an optical light transmission defect: (a) laser source; (b) collimator; (c) fiber cable (NA = 0.27); (d) fiber adapter; (e) fiber connecter; and (f) fiber sensor (NA = 0.37).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3673071&req=5

f10-sensors-13-04067: Diagram of the components of an optical light transmission defect: (a) laser source; (b) collimator; (c) fiber cable (NA = 0.27); (d) fiber adapter; (e) fiber connecter; and (f) fiber sensor (NA = 0.37).
Mentions: The light transmission defect detection method was primarily based on internal optical fiber core propagation by optically coupling the laser to the process. For this study, we used the structure shown in Figure 10 to guide the laser light inside the optical fiber sensor as it propagates. First, an optical collimator was used to focus the laser source (wavelength: 532 nm; power: 10 mW) inside the optical fiber transmission line (NA = 0.27) during light propagation. At this time, light from the source was transmitted to the end with an NA value of 0.27 and then guided through the optical fiber adapter as it propagated within the optical fiber core (NA = 0.37). The Optical fiber core was then examined to confirm that the confined light source was guided to the core of the optical fiber when propagating. A diagram of the measurement is shown in Figure 11. When the surface is irregular or contains debris from processing, according to the optical transmission principle, irregular surfaces in the path of light transmissions cause the light to diffuse. Observation of the light diffusion phenomenon facilitates the achievement of quality analysis objectives.

Bottom Line: Finally, we used the optical fiber sensor fabricated using the improved parameters to measure the refractive indices of various solutions.The results show that a refractive-index resolution of 1.8 × 10(-4) RIU (linear fitting R2 = 0.954) was achieved for sucrose solutions with refractive indices ranging between 1.333 and 1.383.The results provided additional information, specifically, a superior sensor resolution of 5.73 × 10(-5) RIU, and greater linearity at R2 = 0.999.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, National Chung Cheng University, Chiayi 621, Taiwan. saesozj@yahoo.com.tw

ABSTRACT
This study investigates the CO2 laser-stripped partial cladding of silica-based optic fibers with a core diameter of 400 μm, which enables them to sense the refractive index of the surrounding environment. However, inappropriate treatments during the machining process can generate a number of defects in the optic fiber sensors. Therefore, the quality of optic fiber sensors fabricated using CO2 laser machining must be analyzed. The results show that analysis of the fiber core size after machining can provide preliminary defect detection, and qualitative analysis of the optical transmission defects can be used to identify imperfections that are difficult to observe through size analysis. To more precisely and quantitatively detect fabrication defects, we included a tensile test and numerical aperture measurements in this study. After a series of quality inspections, we proposed improvements to the existing CO2 laser machining parameters, namely, a vertical scanning pathway, 4 W of power, and a feed rate of 9.45 cm/s. Using these improved parameters, we created optical fiber sensors with a core diameter of approximately 400 μm, no obvious optical transmission defects, a numerical aperture of 0.52 ± 0.019, a 0.886 Weibull modulus, and a 1.186 Weibull-shaped parameter. Finally, we used the optical fiber sensor fabricated using the improved parameters to measure the refractive indices of various solutions. The results show that a refractive-index resolution of 1.8 × 10(-4) RIU (linear fitting R2 = 0.954) was achieved for sucrose solutions with refractive indices ranging between 1.333 and 1.383. We also adopted the particle plasmon resonance sensing scheme using the fabricated optical fibers. The results provided additional information, specifically, a superior sensor resolution of 5.73 × 10(-5) RIU, and greater linearity at R2 = 0.999.

No MeSH data available.


Related in: MedlinePlus