Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 21 for “"few-mode"”.
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Analysis of Side-Polished Few-Mode Optical Fiber
… field propagating in the cladding of a few-mode fiber. This cladding mode is analyzed and experimentally validated to further the design of a novel class of fiber optic devices. To do this, specific modes are excited in the polished fiber using a phase-only spatial light modulator to …
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Adaptive Mode Control in Few-Mode and Highly Multimode Fibers
Few-mode fibers (FMFs) and multimode fibers (MMFs) can provide much higher data-carrying capacities compared with single-mode fibers. But in order to achieve this goal, one must address the challenge of intermodal coupling and dispersion. Therefore the ability to accurately control the optical …
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Characterization of Optical Coupling and Back-reflection of Few Mode Fibers
… communications industry has caused interest in mode-division multiplexing (MDM) techniques to flourish in recent years. These techniques allow individual waveguide modes to be used as distinct channels. However, as with any versatile technique, it should be also useful and beneficial to extend …
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Modal interference techniques for strain detection in few-mode optical fibers
Interference between the modes of an optical fiber results in specific intensity patterns which can be modulated as a function of disturbances in the optical fiber system. These modulation effects are a direct result of the difference in propagation constants of the constituent modes. In this …
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Investigation of Bragg Gratings in Few-Mode Fibers with a Femtosecond Laser Point-by-Point Technique
The higher-order modes (HOMs) of an optical fiber has been demonstrated as a new dimension to transmitting signals with the development of mode-division multiplexing (MDM) technique. This dissertation aims to explore the HOMs as an extra degree of freedom for device innovation. In particular, with …
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Optical Fibers for Space-Division Multiplexed Transmission and Networking
Single-mode fiber transmission can no longer satisfy exponentially growing capacity demand. Space-division multiplexing (SDM) appears to be the only way able to dramatically improve the transmission capacity, for which, novel optical fiber is one of the key technologies. Such fibers must possess …
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Microwave Spectroscopy and Transport Measurements of Andreev Bound States in Superconductor – Semiconductor Josephson Junctions
… mediated by Andreev bound states in the few mode regime are observed in quantum point contact devices made from this material allowing the possibility of controlling and measuring single Andreev bound states. Josephson junctions coupled to superconducting resonators are measured using …
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High speed optical communication systems: From modulation formats to radically new fibres
… the nonlinear Shannon limit for standard single mode fibre [1,2]. It is in this context that the work on modulation formats, contained in Chapter 3 of this thesis, was undertaken. The work investigates the proposed energy-efficient four-dimensional modulation formats. The work begins by studying …
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Multidimensional fiber quantum light sources and their applications
… fibers support discrete transverse spatial modes that have potential for applications in high-dimensional quantum information processing. When paired with other degrees of freedom such as spectral modes, fibers become a versatile platform for studying multidimensional quantum systems. In …
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Axial strain effects on optical fiber mode patterns
Axial strain effects in multimode fibers are studied. A few-mode fiber is mounted on a tensile testing machine and strained at various speeds. The output of a monochromatic light source passing through it is monitored and recorded. Relations are noted between the light output the magnitude of …
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Probing Power-Absorbing Structures at Near-Infrared Wavelengths using Energy Absorption Interferometry
… characterizing the optical response of single-mode, few-mode and multi- mode power-absorbing structures, such as near-infrared detectors. A detector’s output can be written as the full spatial contraction of the external field correlation tensor and detector response correlation tensor …
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Transition Edge Sensors for Far-Infrared Space Science
… (NEP) of only 10^{-19} WHz^{-1/2}. However, very few TES arrays have so far been developed for these wavelengths, ∼30-200 μm, characterised by an NEP two orders of magnitude lower than necessary in TESs for ground-based microwave astronomy, few-moded optical behaviour and saturation powers of only …
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Robust Data Center Network Design using Space Division Multiplexing
… Multiplexing using multi-core fibers (MCFs), and few-mode fibers (FMFs) has been studied in our work to enhance the data-carrying capacity of optical fibers while minimizing the transmission cost per bit. The objective of our work is to develop a path protection scheme to handle communication …
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Optical fiber modal domain sensors for dynamic strain measurement
Modern engineering structures often incorporate new materials and complex designs for which existing techniques for nondestructive evaluation prove inadequate, especially for dynamic and in-service measurements. At the same time, optical fiber sensors have been identified as an ideal candidate for …
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Numerical Analysis of Optically-induced Long-period Fiber Gratings for Sensing Applications
… ranging from several hundred micrometers to a few millimeters can couple a core mode to discrete co-propagating cladding modes when the phase matching condition is satisfied. The rapid attenuation of cladding modes results in loss bands in the transmission spectrum. As the attenuation bands are …
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Non-Binary Coded Modulation for FMF-Based Coherent Optical Transport Networks
The Internet has fundamentally changed the way of modern communication. Current trends indicate that high-capacity demands are not going to be saturated anytime soon. From Shannon's theory, we know that information capacity is a logarithmic function of signal-to-noise ratio (SNR), but a linear …
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High Resolution Distributed Sensing Using Exposed-Core Fibres
… to two dimensions are detected using the few-mode property of the ECF. The size characterisation of micro-scaled particles has also been demonstrated using machine learning algorithms based on the multimode property of the ECF. The ECF OFDR platform is also demonstrated as a useful tool …
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Beiträge zur Dispersionskompensation basierend auf der Modenkonversion in höhere Moden und der Ausbreitung dieser Moden in Lichtwellenleitern
… special propagation properties of higher order modes in custom-designed optical fibers. After a short introduction of state-of-the-art dispersion techniques and their parameters (chapter 2) the modeling and calculation of propagation properties of a particular mode in an optical fiber with an …
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Modal Optical Studies of Multi-Moded Ultra-Low-Noise Detectors in Far-Infrared
… of theoretical and numerical techniques for modelling the behaviour of partially coherent optical systems and multi-mode detectors. The numerical simulations were carried out for the ultra-low-noise Transition Edge Sensors (TESs) being proposed for use on the SAFARI instrument on the cooled …
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Adaptive Control of Waveguide Modes in Two-Mode Fibers
Few mode fibers and multimode fibers (MMFs) are traditionally regarded as unsuitable for important applications such as communications and sensing. A major challenge in using MMFs for aforementioned applications is how to precisely control the waveguide modes propagating within MMFs. In this …
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