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Ivan Chapalo

Bio: Ivan Chapalo is an academic researcher from Saint Petersburg State Polytechnic University. The author has contributed to research in topics: Multi-mode optical fiber & Interferometry. The author has an hindex of 7, co-authored 19 publications receiving 107 citations.

Papers
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Journal ArticleDOI
TL;DR: In this paper, a new method of analytical representation and numerical simulation of multimode fiber interferometer signals is developed, which can be used for analysis and design of various optical sensor schemes with multimode-fiber interferometers and is also usable for estimating modal noise characteristics in optical systems with undesirable effects of intermodal interference.
Abstract: A new method of analytical representation and numerical simulation of multimode fiber interferometer signals is developed. A system of averaged normalized characteristics, called amplitude and spectral characteristics, is introduced for this end. Interferometer signals generated by fiber length variation or laser frequency modulation were investigated at various parameters of the fiber. Joint usage of amplitude and spectral characteristics proved to substantially broaden the dynamical range of measurements of weak and strong external disturbances of the fiber. The method may be used for analysis and design of various optical sensor schemes with multimode fiber interferometers. It is also usable for estimating modal noise characteristics in optical systems with undesirable effects of intermodal interference.

27 citations

Journal ArticleDOI
TL;DR: In this paper, a multimode fiber interferometer based on the multimode gradient index perfluorinated polymer fiber was investigated for fiber lengths of 20, 80, and 400 meters when fibers were subjected to different perturbation types.
Abstract: In this article, we present an investigation of a multimode fiber interferometer based on a multimode gradient index perfluorinated polymer fiber. The interferometric response of the polymer fiber was investigated for fiber lengths of 20, 80, and 400 m when fibers were subjected to different perturbation types, such as temperature and strain. The results were theoretically investigated using the averaged characteristics approach and compared with those for silica fiber. Practical features specific to polymer fiber multimode interferometers are discussed. The averaged transfer function was measured and compared with theory at two wavelengths. The influence of fiber length on the interferometer's properties was investigated.

17 citations

Journal ArticleDOI
Abstract: Signals of an intermodal fiber interferometer induced by laser optical frequency modulation are studied. Dependences of signal amplitudes and spectra on the laser frequency deviation are examined theoretically and experimentally for various optical fibers. It is established that the sensitivity of the intermodal fiber interferometer to the laser frequency variation essentially depends on the fiber refractive index profile. The minimal sensitivity corresponds to graded-index (α ≈ 2) multimode optical fibers. Step-index optical fibers (α = ∞) are more sensitive to the laser frequency variation by more than a factor of 100.

10 citations

Proceedings ArticleDOI
11 Apr 2019
TL;DR: In this article, three methods of multimode fiber interferometer signal averaging are investigated theoretically and experimentally: the ensemble averaging, the averaging over a long realization, and averaging over transverse coordinates of an output speckle pattern.
Abstract: Three methods of multimode fiber interferometer signal averaging are investigated theoretically and experimentally: the ensemble averaging, the averaging over a long realization, and the averaging over transverse coordinates of an output speckle pattern. The analysis is performed for two wavelengths and two launch conditions of the graded-index multimode fiber: few mode and multimode. Applicability of methods for practical applications is discussed.

10 citations

Proceedings ArticleDOI
01 Oct 2018
TL;DR: In this paper, the ability of external impact location determining in distributed multimode fiber interferometer with continuous coherent fiber excitation is demonstrated based on the use of increasing number of excited mode groups along fiber.
Abstract: The ability of external impact location determining in distributed multimode fiber interferometer with continuous coherent fiber excitation is demonstrated. It is based on the use of increasing number of excited mode groups along fiber.

9 citations


Cited by
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Journal Article
J. Walkup1
TL;DR: Development of this more comprehensive model of the behavior of light draws upon the use of tools traditionally available to the electrical engineer, such as linear system theory and the theory of stochastic processes.
Abstract: Course Description This is an advanced course in which we explore the field of Statistical Optics. Topics covered include such subjects as the statistical properties of natural (thermal) and laser light, spatial and temporal coherence, effects of partial coherence on optical imaging instruments, effects on imaging due to randomly inhomogeneous media, and a statistical treatment of the detection of light. Development of this more comprehensive model of the behavior of light draws upon the use of tools traditionally available to the electrical engineer, such as linear system theory and the theory of stochastic processes.

1,364 citations

Book ChapterDOI
27 Jan 2010

878 citations

Journal ArticleDOI
TL;DR: A system able to classify perturbations according to the place they have been caused along a multimode optical fiber has been designed and results show classifications up to 99% when the system has to categorize among three different locations.
Abstract: Fiber Specklegram Sensors (FSSs) are highly sensitive to external perturbations, however, trying to locate perturbation's position remains as a barely addressed study. In this work, a system able to classify perturbations according to the place they have been caused along a multimode optical fiber has been designed. As proof of concept, a multimode optical fiber has been perturbated in different points, recording the videos of the perturbations in the speckle pattern, processing these videos, training with them a machine learning algorithm, and classifying further perturbations based on the spatial locations they were generated. The results show classifications up to 99% when the system has to categorize among three different locations lowering to 71% when the locations rise to ten.

47 citations

Journal ArticleDOI
TL;DR: In this paper, the authors review the emerging medical and health-field applications of optical fibers, illustrating the new wave for the fabrication of implantable devices, wearable sensors, and photodetection and therapy setups.
Abstract: Optical fibers with the ability to propagate and transfer data via optical signals have been used for decades in medicine. Biomaterials featuring the properties of softness, biocompatibility, and biodegradability enable the introduction of optical fibers' uses in biomedical engineering applications such as medical implants and health monitoring systems. Here, we review the emerging medical and health-field applications of optical fibers, illustrating the new wave for the fabrication of implantable devices, wearable sensors, and photodetection and therapy setups. A glimpse of fabrication methods is also provided, with the introduction of 3D printing as an emerging fabrication technology. The use of artificial intelligence for solving issues such as data analysis and outcome prediction is also discussed, paving the way for the new optical treatments for human health.

29 citations

Journal ArticleDOI
TL;DR: In this paper, a new method of analytical representation and numerical simulation of multimode fiber interferometer signals is developed, which can be used for analysis and design of various optical sensor schemes with multimode-fiber interferometers and is also usable for estimating modal noise characteristics in optical systems with undesirable effects of intermodal interference.
Abstract: A new method of analytical representation and numerical simulation of multimode fiber interferometer signals is developed. A system of averaged normalized characteristics, called amplitude and spectral characteristics, is introduced for this end. Interferometer signals generated by fiber length variation or laser frequency modulation were investigated at various parameters of the fiber. Joint usage of amplitude and spectral characteristics proved to substantially broaden the dynamical range of measurements of weak and strong external disturbances of the fiber. The method may be used for analysis and design of various optical sensor schemes with multimode fiber interferometers. It is also usable for estimating modal noise characteristics in optical systems with undesirable effects of intermodal interference.

27 citations