356 research outputs found
Full-Field, Carrier-Less, Polarization-Diversity, Direct Detection Receiver based on Phase Retrieval
We realize dual-polarization full-field recovery using intensity only
measurements and phase retrieval techniques based on dispersive elements.
30-Gbaud QPSK waveforms are transmitted over 520-km standard single-mode fiber
and equalized from the receiver outputs using 2X2 MIMO
Simple Optimization Method to Determine Best Management Practices to Reduce Phosphorus Loading in Echo Reservoir, Utah
This study develops and applies a simple linear optimization program to identify cost effective Best Management Practices (BMPs) to reduce phosphorus loading to Echo Reservoir, Utah. The optimization program tests the feasibility of proposed Total Maximum Daily Load (TMDL) allocations based on potential BMP options and provides information regarding the spatial redistribution of loads among sub-watersheds. The current version of the TMDL for Echo reservoir allocates phosphorus loads to existing non-point phosphorus sources in different sub-watersheds to meet a specified total load. Optimization results show that it is feasible to implement BMPs for non-point sources in each sub-watershed to meet reduction targets at a cost of $1.0 million. However, relaxing these targets can achieve the overall target at lower cost. The optimization program and results provide a simple tool to test the feasibility of proposed TMDL allocations based on potential BMP options and can also recommend spatial redistributions of loads among sub-watersheds to lower costs
Laguerre-Gaussian mode sorter
Light's spatial properties represent an infinite state space, making it
attractive for applications requiring high dimensionality, such as quantum
mechanics and classical telecommunications, but also inherently spatial
applications such as imaging and sensing. However, there is no demultiplexing
device in the spatial domain comparable to a grating or calcite for the
wavelength and polarisation domains respectively. Specifically, a simple device
capable of splitting a finite beam into a large number of discrete spatially
separated spots each containing a single orthogonal spatial component. We
demonstrate a device capable of decomposing a beam into a Cartesian grid of
identical Gaussian spots each containing a single Laguerre-Gaussian component.
This is the first device capable of decomposing the azimuthal and radial
components simultaneously, and is based on a single spatial light modulator and
mirror. We demonstrate over 210 spatial components, meaning it is also the
highest dimensionality mode multiplexer of any kind
Dual Polarization Full-Field Signal Waveform Reconstruction Using Intensity Only Measurements for Coherent Communications
Conventional optical coherent receivers capture the full electrical field,
including amplitude and phase, of a signal waveform by measuring its
interference against a stable continuous-wave local oscillator (LO). In optical
coherent communications, powerful digital signal processing (DSP) techniques
operating on the full electrical field can effectively undo transmission
impairments such as chromatic dispersion (CD), and polarization mode dispersion
(PMD). Simpler direct detection techniques do not have access to the full
electrical field and therefore lack the ability to compensate for these
impairments. We present a full-field measurement technique using only direct
detection that does not require any beating with a strong carrier LO. Rather,
phase retrieval algorithms based on alternating projections that makes use of
dispersive elements are discussed, allowing to recover the optical phase from
intensity-only measurements. In this demonstration, the phase retrieval
algorithm is a modified Gerchberg Saxton (GS) algorithm that achieves a
simulated optical signal-to-noise ratio (OSNR) penalty of less than 4dB
compared to theory at a bit-error rate of 2 times 10-2. Based on the proposed
phase retrieval scheme, we experimentally demonstrate signal detection and
subsequent standard 2x2 multiple-input-multiple-output (MIMO) equalization of a
polarization-multiplexed 30-Gbaud QPSK transmitted over a 520-km standard
single-mode fiber (SMF) span
Bi-allelic CAMSAP1 variants cause a clinically recognizable neuronal migration disorder
Non-centrosomal microtubules are essential cytoskeletal filaments that are important for neurite formation, axonal transport, and neuronal migration. They require stabilization by microtubule minus-end-targeting proteins including the CAMSAP family of molecules. Using exome sequencing on samples from five unrelated families, we show that bi-allelic CAMSAP1 loss-of-function variants cause a clinically recognizable, syndromic neuronal migration disorder. The cardinal clinical features of the syndrome include a characteristic craniofacial appearance, primary microcephaly, severe neurodevelopmental delay, cortical visual impairment, and seizures. The neuroradiological phenotype comprises a highly recognizable combination of classic lissencephaly with a posterior more severe than anterior gradient similar to PAFAH1B1(LIS1)-related lissencephaly and severe hypoplasia or absence of the corpus callosum; dysplasia of the basal ganglia, hippocampus, and midbrain; and cerebellar hypodysplasia, similar to the tubulinopathies, a group of monogenic tubulin-associated disorders of cortical dysgenesis. Neural cell rosette lineages derived from affected individuals displayed findings consistent with these phenotypes, including abnormal morphology, decreased cell proliferation, and neuronal differentiation. Camsap1-null mice displayed increased perinatal mortality, and RNAScope studies identified high expression levels in the brain throughout neurogenesis and in facial structures, consistent with the mouse and human neurodevelopmental and craniofacial phenotypes. Together our findings confirm a fundamental role of CAMSAP1 in neuronal migration and brain development and define bi-allelic variants as a cause of a clinically distinct neurodevelopmental disorder in humans and mice
Digital Twin of a Network and Operating Environment Using Augmented Reality
We demonstrate the digital twin of a network, network elements, and operating
environment using machine learning. We achieve network card failure
localization and remote collaboration over 86 km of fiber using augmented
reality
Ultrabroadband Polarization Insensitive Hybrid using Multiplane Light Conversion
We designed, fabricated and tested an optical hybrid that supports an octave
of bandwidth (900-1800 nm) and below 4-dB insertion loss using multiplane light
conversion. Measured phase errors are below 3-degree across a measurement
bandwidth of 390 nm.Comment: 3 pages, 4 figures, accepted by OFC 202
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