Dr. Vladimir V. Demidov Profile

Dr. Vladimir V. Demidov

Deputy Chief at S.I. Vavilov State Optical Institute

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Author

Area of Expertise:

Optical fiber technology , Microstructured fibers , Photonic crystal fibers , Optical fiber modeling

Publications (6)

PROCEEDINGS ARTICLE | June 6, 2018

Results of differential mode delay map measurements performed for multimode optical fibers with strong and weak diameter variation

Proc. SPIE. 10774, Optical Technologies in Telecommunications 2017

KEYWORDS: Multimode fibers, Optical fibers, Refractive index, Statistical analysis, Signal attenuation, Manufacturing, Digital micromirror devices, Picosecond phenomena, Analytical research, Laser optics

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PROCEEDINGS ARTICLE | May 23, 2018

Hollow-core antiresonant fibers optimized for operation in the spectral range 0.6-2.5 µm (Conference Presentation)

Proc. SPIE. 10681, Micro-Structured and Specialty Optical Fibres V

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Hollow-core fibers (HCFs) which guide light by an antiresonant reflection from arrays of silica walls have been attracting much interest due to their extraordinary optical properties and potential interdisciplinary applications including highly efficient laser-matter interaction, ultra-short pulse delivery, pulse compression and low-loss mid-infrared transmission. There are several types of HCFs having either a photonic crystal cladding, Kagome lattice or a single cycle of capillaries surrounding the core. In the latter case the antiresonant guidance properties depend strongly on the core size and the shape of the core/cladding boundary. In this work, we focus on the capabilities of two HCF designs (negative curvature of the core/cladding boundary and nodeless capillary structure) to obtain a nearly single-mode guidance from the visible to the mid-infrared spectral regions. The first HCF (Sample A) was drawn from the stack comprising a cycle of eight touching capillaries having the wall thickness 1.5 µm which provided a negative curvature of the core/cladding boundary. The fiber was intentionally manufactured with the trapezoidal shape of the capillaries in order to minimize the interaction between the surface modes, trapped amidst the touching trapezoids, and the fundamental mode in a hollow core. The negative curvature of the boundary resulting in the octagonal shape of the core was achieved by putting an excess gas pressure inside the capillaries during the drawing process. The second HCF (Sample B) was produced from the stack comprising a cycle of six non-touching capillaries having the wall thickness 2.5 µm with a view to restrict the abovementioned interaction via breaking the surface modes coupling between the adjacent capillaries. As in the first case, the gas pressure was controlled carefully to keep all capillaries separately from each other. In both samples the core diameter was equal to 50 µm ensuring a relatively large effective mode area. Taking into account the periodic nature of HCFs transmission windows, we simulated and measured accurately transmission spectra and modal properties of the fibers. The simulations were performed using the finite element analysis. The transmission spectra were measured by passing light from the tungsten halogen lamp through the samples of 35 cm long and registering output signal applying three optical spectrometers covering the wavelength range 600-2500 nm. We observed a good agreement between the simulation and the experiment. The Sample A has transmission windows at the wavelengths 650, 750, 850-900, 950-1050, 1150-1300, 1450-1700, 2000-2300 nm and the Sample B – at the wavelengths 600, 650-700, 750-800, 850-950, 1000-1100, 1150-1350, 1450-1750, 1900-2400 nm. The mid-infrared window for the Sample B is larger and more pronounced in terms of relative transmission due to the larger wall thickness at the core/cladding boundary. Moreover, the Sample B is predicted to be practically single-mode in the considered spectral region, as the losses of the most competitive higher-order modes are estimated to be much above 1 dB/m. A similar regime for the Sample A is expected only when operating at the long-wavelength limit of the spectral region, due to the increase in the fundamental and higher-order modes refractive index difference.

PROCEEDINGS ARTICLE | April 6, 2017

Simulation and analysis of mode staff excitation during “O”-band optical signal launching to graded multimode fiber with large central defect of refractive index profile via standard singlemode fiber

Proc. SPIE. 10342, Optical Technologies for Telecommunications 2016

KEYWORDS: Multimode fibers, Optical fibers, Refractive index, Light sources, Waveguides, Fiber optics, Sensors, Single mode fibers, Digital micromirror devices, Analytical research

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PROCEEDINGS ARTICLE | April 6, 2017

Methods and technique of manufacturing silica graded-index fibers with a large central defect of the refractive index profile for fiber-optic sensors based on few-mode effects

Proc. SPIE. 10342, Optical Technologies for Telecommunications 2016

KEYWORDS: Multimode fibers, Optical fibers, Refractive index, Silica, Cladding, Signal attenuation, Glasses, Fiber optics sensors, Digital micromirror devices, Graded index fibers, Optics manufacturing

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PROCEEDINGS ARTICLE | May 2, 2014

New possibilities of higher-order mode filtering in large-mode-area photonic crystal fibers

Proc. SPIE. 9128, Micro-structured and Specialty Optical Fibres III

KEYWORDS: Optical filters, Refractive index, Photonic crystal fibers, Silica, Cladding, Signal attenuation, Ions, Resistance, Structured optical fibers, Solids

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PROCEEDINGS ARTICLE | April 26, 2012

Large-core microstructured fibers with asymmetric cladding design for practical single-mode operation

Proc. SPIE. 8426, Microstructured and Specialty Optical Fibres

KEYWORDS: Optical fibers, Refractive index, Silica, Cladding, Signal attenuation, Laser applications, Resistance, Structured optical fibers, Raman scattering, Micro optical fluidics

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Showing 5 of 6 publications

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