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Modeling and Characterization of a Novel, Low-Cost, Direct-Write Waveguide
Both the current long-term telecommunication trends toward optical networking and the
recent growth in information bandwidth have pushed the necessity for improved optical
communications. Our fabrication approach, which leverages our expertise in solid
freeform fabrication in conjunction with sol-gel technology, has advantages over these
other methods because of the inherent benefits of using a direct-write philosophy, such as
design flexibility and minimal post-processing. However, fabrication of such novel
optical components requires extensive knowledge of their light guidance capabilities.
This paper will show the technical issues involved in both modeling and characterizing
small optical components fabricated by locally densifying sol-gels in a modified directwrite process.Mechanical Engineerin
Multi-dimensional entanglement generation with multi-core optical fibers
Trends in photonic quantum information follow closely the technical progress
in classical optics and telecommunications. In this regard, advances in
multiplexing optical communications channels have also been pursued for the
generation of multi-dimensional quantum states (qudits), since their use is
advantageous for several quantum information tasks. One current path leading in
this direction is through the use of space-division multiplexing multi-core
optical fibers, which provides a new platform for efficiently controlling
path-encoded qudit states. Here we report on a parametric down-conversion
source of entangled qudits that is fully based on (and therefore compatible
with) state-of-the-art multi-core fiber technology. The source design uses
modern multi-core fiber beam splitters to prepare the pump laser beam as well
as measure the generated entangled state, achieving high spectral brightness
while providing a stable architecture. In addition, it can be readily used with
any core geometry, which is crucial since widespread standards for multi-core
fibers in telecommunications have yet to be established. Our source represents
an important step towards the compatibility of quantum communications with the
next-generation optical networks.Comment: 9 pages, 7 figure
End-to-End Learning in Optical Fiber Communications: Experimental Demonstration and Future Trends
Fiber-optic auto-encoders are demonstrated on an intensity modulation/direct detection testbed, outperforming state-of-the-art signal processing. Algorithms for end-to-end optimization using experimentally collected data are discussed. The end-to-end learning framework is extended for performing optimization of the symbol distribution in probabilistically-shaped coherent systems
Adaptive Optics pre-compensated laser uplink to LEO and GEO
We present the results from a Monte Carlo computer simulation of adaptive optics (AO) pre-compensated laser uplink propagation through the Earth’s atmospheric turbulence from the ground to orbiting satellites. The simulation includes the so-called point-ahead angle and tests several potential AO mitigation modes such as tip/tilt or full AO from the downlink beam, and a laser guide star at the point ahead angle. The performance of these modes, as measured by metrics relevant for free-space optical communication, are compared with no correction and perfect correction. The aim of the study is to investigate fundamental limitations of free-space optical communications with AO pre-compensation and a point-ahead angle, therefore the results represent an upper bound of AO corrected performance, demonstrating the potential of pre-compensation technology. Performance is assessed with varying launch aperture size, wavelength, launch geometry, ground layer turbulence strength (i.e. day/night), elevation angle and satellite orbit (Low-Earth and Geostationary). By exploring this large parameter space we are able examine trends on performance with the aim of informing the design of future optical ground stations and demonstrating and quantifying the potential upper bounds of adaptive optics performance in free-space optical communications
Performance analysis of interferometric noise due to unequally powered interferers in optical networks
Interferometric crosstalk has been identified as the cause of performance limits in future transparent all-optical networks. A large number of studies have been conducted on this phenomenon using a vast array of evaluation techniques. However, most major studies have considered that although the interfering terms may differ in number, the power contribution that they all make will be identical for all interfering terms. Although this situation is easy to analyze, it does not necessarily represent the situation that is likely to occur in a real network, which will be constructed of nodes with different degrees of connectivity, quite possibly from different vendors, and therefore with differing crosstalk characteristics. This paper describes a study on the impact of unequally powered interfering terms using a rigorous analysis technique. To validate the use of the chosen technique, the paper begins by bench-marking a number of common evaluation techniques against empirically derived, experimentally verified noise performance formulas
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