7,742 research outputs found
Emerging applications of integrated optical microcombs for analogue RF and microwave photonic signal processing
We review new applications of integrated microcombs in RF and microwave
photonic systems. We demonstrate a wide range of powerful functions including a
photonic intensity high order and fractional differentiators, optical true time
delays, advanced filters, RF channelizer and other functions, based on a Kerr
optical comb generated by a compact integrated microring resonator, or
microcomb. The microcomb is CMOS compatible and contains a large number of comb
lines, which can serve as a high performance multiwavelength source for the
transversal filter, thus greatly reduce the cost, size, and complexity of the
system. The operation principle of these functions is theoretically analyzed,
and experimental demonstrations are presented.Comment: 16 pages, 8 figures, 136 References. Photonics West 2018 invited
paper, expanded version. arXiv admin note: substantial text overlap with
arXiv:1710.00678, arXiv:1710.0861
Can COVID-19 vaccinations cause chronic urticaria?
Rationale: Adverse reactions to COVID-19 vaccinations have garnered significant attention from both the public and medical community. Delayed onset urticaria has been described as an adverse reaction to COVID-19 vaccination, but this phenotype has not been fully characterized thus specific evaluation and treatment strategies have not been developed.
Methods: We conducted a retrospective chart review of patients presenting for evaluation of urticaria (acute or chronic) to the University of Washington Allergy Clinics between 12/14/2020 and 12/14/2021. Records were reviewed for development of delayed onset, persistent urticaria occurring following receipt of a COVID-19 vaccination or a history of chronic spontaneous urticaria that worsened after COVID-19 vaccination. Demographic and clinical data including age, sex, co-morbid conditions, treatments attempted, and treatment response was obtained.
Results: 22 total patients were determined to have urticaria thought to be attributed to Pfizer and Moderna COVID-19 vaccinations. Six of the 22 (27%) had pre-existing chronic spontaneous urticaria (CSU) which worsened notably after vaccination, and 16 (73%) had novel development of delayed urticaria following vaccination. Patients received a range of treatments including H1-antihistamines, H2-antihistamines, leukotriene inhibitors, oral steroids, omalizumab, cyclosporine, and acupuncture. The majority of patients had improvement or resolution while a minority had worsening urticaria despite treatments at the time of evaluation.
Conclusions: COVID-19 vaccinations may result in the development of chronic urticaria in select patients and may worsen control of urticaria in some patients with previously diagnosed chronic urticaria. Additional studies are needed to characterize these patients and determine optimal management strategies
Photonic RF and microwave reconfigurable filters and true time delays based on an integrated optical Kerr frequency comb source
We demonstrate advanced transversal radio frequency (RF) and microwave
functions based on a Kerr optical comb source generated by an integrated
micro-ring resonator. We achieve extremely high performance for an optical true
time delay aimed at tunable phased array antenna applications, as well as
reconfigurable microwave photonic filters. Our results agree well with theory.
We show that our true time delay would yield a phased array antenna with
features that include high angular resolution and a wide range of beam steering
angles, while the microwave photonic filters feature high Q factors, wideband
tunability, and highly reconfigurable filtering shapes. These results show that
our approach is a competitive solution to implementing reconfigurable, high
performance and potentially low cost RF and microwaveComment: 15 pages, 11 Figures, 60 Reference
Pulsed Quantum Frequency Combs from an Actively Mode-locked Intra-cavity Generation Scheme
We introduce an intra-cavity actively mode-locked excitation scheme for nonlinear microring resonators that removes the need for external laser excitation in the generation of pulsed two-photon frequency combs. We found a heralded anti-bunching dip of 0.245 and maximum coincidence-to-accidental ratio of 110 for the generated photon pairs
On-chip Quantum State Generation by Means of Integrated Frequency Combs
Summary form only given. This paper investigates different approaches to generate optical quantum states by means of integrated optical frequency combs. These include the generation of multiplexed heralded single-photons, the first realization of cross-polarized photon-pairs on a photonic chip, the first generation of multiple two-photon entangled states, and the first realizations of multi-photon entangled quantum states on a photonic chip
Generation of Complex Quantum States Via Integrated Frequency Combs
The generation of optical quantum states on an integrated platform will enable low cost and accessible advances for quantum technologies such as secure communications and quantum computation. We demonstrate that integrated quantum frequency combs (based on high-Q microring resonators made from a CMOS-compatible, high refractive-index glass platform) can enable, among others, the generation of heralded single photons, cross-polarized photon pairs, as well as bi- and multi-photon entangled qubit states over a broad frequency comb covering the S, C, L telecommunications band, constituting an important cornerstone for future practical implementations of photonic quantum information processing
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