scholarly journals Intrinsic Point Defects in Silica for Fiber Optics Applications

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7682
Author(s):  
Giuseppe Mattia Lo Piccolo ◽  
Marco Cannas ◽  
Simonpietro Agnello
Keyword(s):  
Optical Properties ◽  
Fiber Optics ◽  
Optical Fibers ◽  
Point Defects ◽  
Transmission Efficiency ◽  
Widespread Application ◽  
Intrinsic Point Defects ◽  
Pure Silica ◽  
Laser Systems ◽  
Structure Reactivity Relationship

Due to its unique properties, amorphous silicon dioxide (a-SiO2) or silica is a key material in many technological fields, such as high-power laser systems, telecommunications, and fiber optics. In recent years, major efforts have been made in the development of highly transparent glasses, able to resist ionizing and non-ionizing radiation. However the widespread application of many silica-based technologies, particularly silica optical fibers, is still limited by the radiation-induced formation of point defects, which decrease their durability and transmission efficiency. Although this aspect has been widely investigated, the optical properties of certain defects and the correlation between their formation dynamics and the structure of the pristine glass remains an open issue. For this reason, it is of paramount importance to gain a deeper understanding of the structure–reactivity relationship in a-SiO2 for the prediction of the optical properties of a glass based on its manufacturing parameters, and the realization of more efficient devices. To this end, we here report on the state of the most important intrinsic point defects in pure silica, with a particular emphasis on their main spectroscopic features, their atomic structure, and the effects of their presence on the transmission properties of optical fibers.

Effect of intrinsic point defects on the electronic and optical properties of Ho:BYF crystal

2021 ◽  
Vol 121 ◽  
pp. 111514
Author(s):  
Lihong Han ◽  
Yuanyuan Zou ◽  
Jia Liu ◽  
Baonan Jia ◽  
Gang Liu ◽  
...  
Keyword(s):  
Optical Properties ◽  
Point Defects ◽  
Electronic And Optical Properties ◽  
Intrinsic Point Defects

New Accessory for Characterizing Optical Fibers with an FT-IR Spectrometer

1994 ◽  
Vol 48 (7) ◽  
pp. 852-856 ◽  
Author(s):  
S. Lowry ◽  
T. May ◽  
A. Bornstein ◽  
Y. Weissman ◽  
R. Harman ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Optical Properties ◽  
Fiber Optics ◽  
Optical Fibers ◽  
Fiber Optic ◽  
Spectral Response ◽  
Spectral Transmission ◽  
Acceptance Angle ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

An accessory has been designed for FT-IR spectroscopy that can be used to measure the optical properties of fiber-optic cables or serve as an interface for remote sensing probes that use fiber optics. This accessory utilizes compound parabolic concentrators (CPCs) to focus the energy from the spectrometer into the optical fiber and to also refocus the energy returning to the spectrometer onto the detector. The design was optimized for the high acceptance angle of chalcogenide mid-IR fibers. However, the use of nonimaging concentrators yields an all-reflecting system that can be used to characterize fibers with different spectral transmission ranges. This accessory has been used to investigate the spectral response, cladding effects, and impurities in various optical fibers.

Hole-Assisted Lightguide Fiber - A Practical Derivative of Photonic Crystal Fiber

2002 ◽  
Vol 722 ◽  
Author(s):  
Takemi Hasegawa ◽  
Eisuke Sasaoka ◽  
Masashi Onishi ◽  
Masayuki Nishimura ◽  
Yasuhide Tsuji ◽  
...  
Keyword(s):  
Optical Properties ◽  
Photonic Crystal ◽  
Group Velocity ◽  
Fiber Optics ◽  
Optical Fibers ◽  
Velocity Dispersion ◽  
Transmission Loss ◽  
Photonic Bandgap ◽  
Group Velocity Dispersion ◽  
Microstructured Fibers

AbstractUsage of air holes in optical fibers has become a hot subject in fiber optics because of the possibilities for novel transmission properties. Although photonic crystal fibers based on photonic bandgap guidance are the most drastic innovation in this subject, optical fibers containing air holes but not having photonic crystal structures are also being intensively studied. Such air-silica microstructured fibers are more practical than the photonic bandgap fibers because the lack of photonic crystal structure makes the fabrication far easier. Even without the photonic bandgap, the microstructured fibers can exhibit valuable properties in terms of group velocity dispersion and nonlinearity, because the index contrast between air and silica is 10 or more times as large as that of the conventional optical fibers based on doped silica glasses. However, one of the major challenges for practical applications of the air-silica microstructured fibers has been their high transmission losses, which have been several tens to hundreds times higher than those of the conventional fibers. As a solution to this problem, we have proposed a more practical structure called hole-assisted lightguide fiber (HALF). In addition to the air holes for realizing novel optical properties, this structure has a material index profile for waveguiding, and hence is closer to the conventional fibers than the other microstructured fibers are. As a result, novel optical properties can be realized without severe degradation in transmission loss. In experiments, an anomalous group velocity dispersion as large as +35 ps/nm/km at 1550 nm wavelength, which would be unattainable in the conventional fibers, has been realized with a loss of 0.41 dB/km, which is comparable to those of the conventional fibers. Analyses of the losses of the fabricated HALFs suggest that the loss should be lowered by mitigating the effect of the drawing tension and minimizing the power fraction in the holes. It is also shown that the full-vector finite element method realizes accurate modeling of the properties such as dispersion and macrobend loss.

Spectroscopic Study of $\gamma$-Ray and Pulsed X-Ray Radiation-Induced Point Defects in Pure-Silica-Core Optical Fibers

2007 ◽  
Vol 54 (4) ◽  
pp. 1136-1142 ◽  
Author(s):  
S. Girard ◽  
Y. Ouerdane ◽  
B. Vincent ◽  
J. Baggio ◽  
K. Medjahdi ◽  
...  
Keyword(s):  
Spectroscopic Study ◽  
Optical Fibers ◽  
Point Defects ◽  
Gamma Ray ◽  
X Ray ◽  
Pure Silica ◽  
Radiation Induced ◽  
Silica Core

Effect of Mn3+ doping on crystal structure, point defects, and optical properties in green Ca3(VO4)2 single crystals

2021 ◽  
pp. 111300
Author(s):  
Galina M. Kuz’micheva ◽  
Liudmila. I. Ivleva ◽  
Irina A. Kaurova ◽  
Evgeny V. Khramov ◽  
Victor B. Rybakov ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Optical Properties ◽  
Single Crystals ◽  
Point Defects

scholarly journals Polymer Dispersed Cholesteric Liquid Crystals With a Toroidal Director Configuration under an Electric Field

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 732
Author(s):  
Anna P. Gardymova ◽  
Mikhail N. Krakhalev ◽  
Victor Ya. Zyryanov ◽  
Alexandra A. Gruzdenko ◽  
Andrey A. Alekseev ◽  
...  
Keyword(s):  
Optical Properties ◽  
Liquid Crystal ◽  
Electric Field ◽  
Point Defects ◽  
Structural Response ◽  
Optical Filters ◽  
Response Curves ◽  
Polymer Dispersed Liquid Crystal ◽  
Dichroic Dye ◽  
Polymer Dispersed

The electro-optical properties of polymer dispersed liquid crystal (PDLC) films are highly dependent on the features of the contained liquid crystal (LC) droplets. Cholesteric LC droplets with homeotropic boundaries can form several topologically different orientational structures, including ones with single and more point defects, layer-like, and axisymmetric twisted toroidal structures. These structures are very sensitive to an applied electric field. In this work, we have demonstrated experimentally and by computer simulations that twisted toroidal droplets reveal strong structural response to the electric field. In turn, this leads to vivid changes in the optical texture in crossed polarizers. The response of droplets of different sizes were found to be equivalent in terms of dimensionless parameters. In addition, the explanation of this phenomenon showed a comparison of theoretical and experimental structural response curves aids to determine the shape of the droplet. Finally, we demonstrated that the addition of a dichroic dye allows such films to be used as optical filters with adjustable color even without polarizers.

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