Dr. Ali A. Jasim Profile

Dr. Ali A. Jasim

Research Scientist at Institute of Photonics and Electronics of the CAS vvi

SPIE Involvement:

Author

Area of Expertise:

Fiber Lasers and Nonlinear Optics , Specialty Optical Fibers , Optical Mirco/Nanofibers devices , Optical Sensors

Websites:

Personal Website | Company Website

Publications (5)

Proceedings Article | 30 May 2023 Poster + Paper

Adjusting the transmission bands of the negative curvature hollow-core fibers

A. Jasim, A. Borodkin, M. Grábner, O. Podrazký, P. Honzátko

Proceedings Volume 12573, 125730Y (2023) https://doi.org/10.1117/12.2665709

KEYWORDS: Capillaries, Gas lasers, Optical transmission, Mid-IR, Ultraviolet radiation, Fiber lasers, Fusion splicing, Structured optical fibers, Tapered optical fibers, Heat treatments, Carbon dioxide lasers

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Antiresonant negative curvature hollow-core optical fibers (NC-HCFs) have proven to have great potential for the delivery of high-energy pulses and for continuous wave Mid-infrared fiber gas laser (FGL) systems. However, following the drawing fiber conditions on the designed fiber geometry, the resulting position of transmission bands of the NC-HCFs needs to be matched to both pumping and lasing wavelengths for the FGL with the particular filled gas. In this work, we investigated experimentally the possibilities of adjusting the transmission bands of a short length of the fabricated NC-HCFs to both UV the Mid-infrared directions that would further enhance their usage in FGL. The investigation was based on two steps. The first step involves fabricating a few fibers from a single preform with different inner geometry dimensions concerning the applied pressure into the preform’s capillaries. This would help to calibrate the correlation of adjusted fibers’ transmission bands to the desired wavelength with respect to the applied pressure while drawing. Increasing the pressure into the capillaries from 300 to 400 mm H₂O while maintaining the pressure in the preform core at 30 mm H₂O the bands were gradually blue-shifted by ~16.5 % to have about 330 nm shift at the first transmission band. This is attributed to the decrease in core diameter, capillaries gaps, and wall-thickness while increasing the capillaries diameter. The second step involves processing a short length of drawn fibers through local heating and tapering for adjusting their transmission bands' positions using a CO₂ laser fusion splicer. Processing the whole length of a short fiber segment ~5 cm shows a complete redshift by ~12.2 % and a blueshift by ~10.2 % after heating and tapering respectively. The first transmission band of the processed fiber was shifted about 200 nm after heating and 122 nm after tapering. The parameters of processing were optimized; thus, no insertion losses were observed. Such results urge us to further develop the mechanism of processing fibers to process long lengths of fibers in the future.

Proceedings Article | 18 April 2021 Poster + Presentation + Paper

Thulium-doped fiber performance optimization via fiber bending and twisting and inner-cladding shape design

O. Schreiber, J. Aubrecht, A. A. Jasim, F. Todorov, P. Honzátko

Proceedings Volume 11773, 117731A (2021) https://doi.org/10.1117/12.2592309

KEYWORDS: Fiber lasers, Absorption, Cladding, Resonators, Carbon dioxide lasers, Signal attenuation, Semiconductor lasers, Optical fibers, Numerical modeling, Medicine

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Proceedings Article | 1 April 2020 Presentation + Paper

Numerical modelling of pump absorption in coiled and twisted double-clad fiber: a prospect for tandem pumped fiber laser

Martin Grábner, Kanagaraj Nithyanandan, Pavel Peterka, Pavel Koška, Pavel Honzátko, Ali Jasim

Proceedings Volume 11355, 113550W (2020) https://doi.org/10.1117/12.2557230

KEYWORDS: Absorption, Cladding, Fiber lasers, Numerical modeling, Holmium, Refractive index, Structured optical fibers, Numerical stability

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Proceedings Article | 1 April 2020 Presentation

Reduction of water penetration into optical fiber preforms for improving preform shaping based on CO2 laser (Conference Presentation)

Ali Jasim, Ondrej Podrazký, Pavel Peterka, Michal Kamrádek, Filip Todorov, Pavel Honzátko

Proceedings Volume 11355, 113550B (2020) https://doi.org/10.1117/12.2555882

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Proceedings Article | 16 April 2019 Paper

Experimental investigation and characterization of fabrication shaped clad optical fiber by thermally polishing optical fiber preforms with CO2 laser

A. Jasim, O. Podrazký, P. Peterka, F. Todorov, P. Honzátko

Proceedings Volume 11029, 1102909 (2019) https://doi.org/10.1117/12.2520995

KEYWORDS: Optical fibers, Polishing, Gas lasers, Silica, Polymers, Carbon monoxide, Absorption, Carbon dioxide lasers, Surface finishing, Signal attenuation, High power fiber lasers

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