1,721,140 research outputs found
Dataset for Temperature insensitive fiber interferometry
No full textData supporting the paper Zhu, Wenwu ; Numkam Fokoua, Eric ; Chen, Yong ; Bradley, Thomas ; Petrovich, Marco ; Poletti, Francesco ; Zhao, Mingshan ; Richardson, David ; Slavík, Radan. / Temperature insensitive fiber interferometry. In: Optics Letters. 2019</span
Ultralow loss and wide bandwidth hollow-core photonic bandgap fibres for telecom applications
No full textLight guidance in air has significant potential in diverse photonics applications, one of hich is optical communications where it may be key to achieving lower attenuation and optical nonlinearity than in conventional silica fibres. This thesis presents research conducted as part of the EU FP7 project MODEGAP, and is concerned with the design of hollow-core photonic bandgap fibres (HC-PBGFs) with low loss and wide bandwidths suitable for high capacity data transmission.In these fibres, loss is dominated by scattering from surface roughness and is subject to the design of the fibre cross-section. Using the criterion of reduced guided mode-field intensity at the interfaces, we conduct detailed finite element simulations which allow to identify preferable structures. A theory of light scattering from surface roughness in HC-PBGFs is then derived, and expressions are obtained which combine statistical information on the roughness and the guided mode-field overlap with scattering surfaces to predict the far-field scattering pattern and the fibre loss.A model based on mass conservation is proposed to predict the properties of HC-PBGFs from knowledge of the preforms from which they are made, and this in turn allows optimizing the design of such preforms. A method allowing accurate modelling of fabricated HC-PBGFs from scanning electron micrographs of their cross-sections is devised and such simulations indicate that structural distortions in the fibre cross-section cause higher field intensities near the interfaces, and hence higher losses. Systematic studies of distortions are then conducted, and it is found that not all distortions are equally detrimental. Combining these findings and using realistic estimates, a HC-PBGF design with 37 cell core defect and loss as low as 0.2dB/km over 580nm of bandwidth near the wavelength of 2µm is presented
Data for "How to make the propagation time through an optical fiber fully insensitive to temperature variations"
No full textData for the manuscript:
Numkam Fokoua, E., and Slavik, R. (2017). How to make the propagation time through an optical fiber fully insensitive to temperature variations. Optica.</span
Impact of structural distortions on the loss properties of hollow-core photonic bandgap fibers
No full textWe present a systematic method for designing hollow-core photonic bandgap fiber geometries with arbitrary structural distortions. Fully vectorial finite element simulations on fibres with realistically distorted claddings reveal that while some distortions are detrimental, a rearrangement of the core surround may reduce the loss by a factor as high as 2.4 compared to "ideal" fibers with no penalty on bandwidth
Understanding the physical origin of surface modes and practical rules for their suppression
No full textNon-destructive structural characterisation of double nested antiresonant nodeless fiber
No full textWe present a side-scattering method for accurate, rapid and non-destructive measurement of double nested antiresonant nodeless fiber (DNANF) microstructure. The diameters of all nested tubular capillaries are measured with sub-micron accuracy.</p
Accurate Modelling of Fabricated Hollow-Core Photonic Bandgap Fibers
No full textWe report a novel approach to reconstruct the cross-sectional profile of fabricated hollow-core photonic bandgap fibers from scanning electron microscope images. Finite element simulations on the reconstructed geometries achieve a remarkable match with the measured transmission window, surface mode position and attenuation. The agreement between estimated scattering loss from surface roughness and measured loss values indicates that structural distortions, in particular the uneven distribution of glass across the thin silica struts on the core boundary, have a strong impact on the loss. This provides insight into the differences between idealized models and fabricated fibers, which could be key to further fiber loss reduction.</span
Longitudinal non-destructive characterization of nested antiresonant nodeless fiber microstructure geometry and twist
No full textWe demonstrate non-destructive measurement of nested antiresonant nodeless fiber (NANF) microstructure along 2.2 km of fiber using a side-scattering method. Additionally, using the same technique, we demonstrate measurement of twisting in NANF.</p
Limits of coupling efficiency into hollow-core antiresonant fibers
No full textWe show theoretically that the coupling efficiency between a gaussian beam and the fundamental mode of nested antiresonant hollow-core optical fibers exceeds 97% and depends on the order of the antiresonance window
Designing multi-mode anti-resonant hollow-core fibers for industrial laser power delivery
No full textWe investigate the design of hollow-core fibers for the delivery of 10s of kilowatt average power from multi-mode laser sources. For such lasers, delivery through solid-core fibers is typically limited by nonlinear optical effects to 10s of meters of distance. Techniques are presented here for the design of multi-mode anti-resonant fibers that can efficiently couple and transmit light from these lasers. By numerical simulation we analyze the performance of two anti-resonant fibers targeting continuous-wave lasers with M
2 up to 13 and find they are capable of delivering MW-level power over several kilometers with low leakage loss, and at bend radii as small as 35 cm. Pulsed lasers are also investigated and numerical simulations indicate that optimized fibers could in principle deliver nanosecond pulses with greater than 100 mJ pulse energy over distances up to 1 km. This would be orders of magnitude higher power and longer distances than in typical machining applications using the best available solid core fibers.
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