The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Zhi Wang - One of the best experts on this subject based on the ideXlab platform.
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Twist-Related Speckle Variation in Graded-Index Multimode Fiber
IEEE Photonics Journal, 2018Co-Authors: Hongye Li, Hu Liang, Zhi WangAbstract:We theoretically investigate a twist-related speckle variation in a graded-index Multimode Fiber. The simulation results show that by increasing the offset splicing distance between a single-mode Fiber and a Multimode Fiber, the speckle pattern tends to be more chaotic. Also, the Fiber length is a crucial parameter that affects speckle distribution, and the speckle pattern varies periodically along the torsional-less Multimode Fiber. By exerting twist on a Multimode Fiber, the speckle pattern revolves. The rotational angle ascends linearly with a twist angle and this tendency is not affected by an offset distance and a Fiber length. The theoretic results disclose a twist-related coupling in the graded-index Multimode Fiber, provide a novel twist sensing method and show potential application in a high-power laser and an imaging field.
P.w. Smith - One of the best experts on this subject based on the ideXlab platform.
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Multimode Fiber Bragg Grating Wavelength Filter in a 10-Gb/s System
IEEE Photonics Technology Letters, 2008Co-Authors: Xijia Gu, W. Mohammed, P.w. SmithAbstract:A 10-Gb/s transmission experiment has been performed on multishell Multimode Fiber Bragg gratings. The device can simultaneously serve as wavelength filter and mode selector and is compatible with conventional graded refractive index Multimode Fiber (MMF) components. This could be a promising technology for wavelength-division multiplexing and mode diversity in practical MMF-based optical access networks.
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Demonstration of all-Fiber WDM for Multimode Fiber local area networks
IEEE Photonics Technology Letters, 2006Co-Authors: X.j. Gu, W. Mohammed, P.w. SmithAbstract:We have successfully demonstrated wavelength-division multiplexing in a conventional 62.5-μm diameter graded index Multimode Fiber using a Fiber Bragg grating written on a novel multicylindrical shell Multimode Fiber. The performance parameters of the device, such as insertion loss and interband and intraband isolations, are presented. The issues and improvements of the device are discussed.
Sung H Baek - One of the best experts on this subject based on the ideXlab platform.
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single mode raman Fiber laser based on a Multimode Fiber
Optics Letters, 2004Co-Authors: Sung H BaekAbstract:Single-mode operation of a Raman Fiber laser based on a Multimode Fiber has been demonstrated for what is to our knowledge the first time. Single-mode operation was achieved through the beam cleanup effect of stimulated Raman scattering in Multimode Fibers. The Raman laser, consisting of a 50‐µm-core Multimode Fiber and a Multimode Nd:YAG laser pump, produced an output beam corresponding to the fundamental mode of the Fiber. The measured beam quality factor M2 of the Raman laser beam was 1.66.
Hongye Li - One of the best experts on this subject based on the ideXlab platform.
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Twist-Related Speckle Variation in Graded-Index Multimode Fiber
IEEE Photonics Journal, 2018Co-Authors: Hongye Li, Hu Liang, Zhi WangAbstract:We theoretically investigate a twist-related speckle variation in a graded-index Multimode Fiber. The simulation results show that by increasing the offset splicing distance between a single-mode Fiber and a Multimode Fiber, the speckle pattern tends to be more chaotic. Also, the Fiber length is a crucial parameter that affects speckle distribution, and the speckle pattern varies periodically along the torsional-less Multimode Fiber. By exerting twist on a Multimode Fiber, the speckle pattern revolves. The rotational angle ascends linearly with a twist angle and this tendency is not affected by an offset distance and a Fiber length. The theoretic results disclose a twist-related coupling in the graded-index Multimode Fiber, provide a novel twist sensing method and show potential application in a high-power laser and an imaging field.
Christophe Moser - One of the best experts on this subject based on the ideXlab platform.
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Delivery of ultrashort spatially focused pulses through a Multimode Fiber
Proceedings of SPIE, 2015Co-Authors: Edgar E. Morales-delgado, Salma Farahi, Ioannis N. Papadopoulos, Demetri Psaltis, Christophe MoserAbstract:Multimode optical Fibers potentially allow the transmission of larger amounts of information than their single mode counterparts because of their high number of supported modes. However, propagation of a light pulse through a Multimode Fiber suffers from spatial distortions due to the superposition of the various exited modes and from time broadening due to modal dispersion. We present a method based on digital phase conjugation to selectively excite in a Multimode Fiber specific optical Fiber modes that follow similar optical paths as they travel through the Fiber. The excited modes interfere constructively at the Fiber output generating an ultrashort spatially focused pulse. The excitation of a limited number of modes following similar optical paths limits modal dispersion, allowing the transmission of the ultrashort pulse. We have experimentally demonstrated the delivery of a focused spot of pulse width equal to 500 fs through a 30 cm, 200 micrometer core step-index Multimode Fiber. The results of this study show that two-photon imaging capability can be added to ultra-thin lensless endoscopy using commercial Multimode Fibers.
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Complex pattern projection through a Multimode Fiber
Proceedings of SPIE, 2015Co-Authors: Damien Loterie, Salma Farahi, Demetri Psaltis, Christophe MoserAbstract:Wavefront shaping through Multimode Fibers has many interesting applications, such as micromanipulation and endoscopy, where the small diameter of Fibers is an advantage in terms of miniaturization. However, pattern projection can suffer from deleterious interference effects depending on the measurement conditions. We experimentally demonstrate the projection of high quality patterns through a Multimode Fiber by correcting for phase drifts while measuring the transmission matrix, and by controlling both the amplitude and the phase of the wavefront sent to the Fiber. We also use the matrix in the reverse direction by reconstructing a distal image from a proximally measured speckle field. This opens up new possibilities for imaging through a Multimode Fiber by decoding wavefronts travelling both ways along the Fiber.
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Multimode Fiber based endoscope
Frontiers in Optics, 2013Co-Authors: Salma Farahi, Ioannis N. Papadopoulos, Christophe Moser, Demetri PsaltisAbstract:We propose a high-resolution lensless endoscope based on a Multimode Fiber and digital scanning. Taking advantage of the high number of degrees of freedom allows for an ultra-thin rigid endoscope with a sub-micron resolution.
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dynamic bending compensation while focusing through a Multimode Fiber
Optics Express, 2013Co-Authors: Salma Farahi, Ioannis N. Papadopoulos, Demetri Psaltis, David Ziegler, Christophe MoserAbstract:Multimode Fiber endoscopes have recently been shown to provide sub-micrometer resolution, however, imaging through a Multimode Fiber is highly sensitive to bending. Here we describe the implementation of a coherent beacon source placed at the distal tip of the Multimode Fiber, which can be used to compensate for the effects of bending. In the first part of this paper, we show that a diffraction limited focused spot can be generated at the distal tip of the Multimode Fiber using the beacon. In the second part, we demonstrate focusing even when the Fiber is bent by dynamically compensating for it. The speckle pattern at the proximal Fiber end, generated by the beacon source placed at its distal end, is highly dependent on the Fiber conformation. We experimentally show that by intensity correlation, it is possible to identify the Fiber conformation and maintain a focus spot while the Fiber is bent over a certain range. Once the Fiber configuration is determined, previously calibrated phase patterns could be stored for each Fiber conformation and used to scan the distal spot and perform imaging.