Publications by authors named "Daniel Perez-Lopez"

A general-purpose photonic processor can be built integrating a silicon photonic programmable core in a technology stack comprising an electronic monitoring and controlling layer and a software layer for resource control and programming. This processor can leverage the unique properties of photonics in terms of ultra-high bandwidth, high-speed operation, and low power consumption while operating in a complementary and synergistic way with electronic processors. These features are key in applications such as next-generation 5/6 G wireless systems where reconfigurable filtering, frequency conversion, arbitrary waveform generation, and beamforming are currently provided by microwave photonic subsystems that cannot be scaled down.

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A variety of topological Hamiltonians have been demonstrated in photonic platforms, leading to fundamental discoveries and enhanced robustness in applications such as lasing, sensing, and quantum technologies. To date, each topological photonic platform implements a specific type of Hamiltonian with inexistent or limited reconfigurability. Here, we propose and demonstrate different topological models by using the same reprogrammable integrated photonics platform, consisting of a hexagonal mesh of silicon Mach-Zehnder interferometers with phase shifters.

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We report an end-to-end analytic model for the computation of the figures of nerit (FOMs) of arbitrarily filtered and amplified heterodyne coherent microwave photonics (MWP) links. It is useful for evaluating the performance of complex systems where the final stage is employed for up/down-converting the radio frequency (RF) signal. We apply the model to a specific case of complex system representing the front-haul segment in a 5G link between the central office and the base station.

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This investigation was aimed at determining the time intervals from the presenting symptoms until the beginning of oral cancer treatment and their relative contribution to the total time, and to assess the impact of the presenting symptom on diagnostic timelines and patient referral routes. A cross-sectional, ambispective study was designed to investigate symptomatic incident cases. The Aarhus statement was used as a conceptual framework.

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Microwave photonic (MWP) links and systems will have more losses as their complexities increase and there will be a need for incorporating optical amplification. Here, we report results of an analytical model developed for amplified arbitrary filtered MWP systems that provides the expressions of the main figures of merit for intensity modulation direct detection. It contemplates the cases of power, intermediate and pre amplification.

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General-purpose programmable photonic processors rely on the large-scale integration of beamsplitters and reconfigurable phase shifters, distributed within unit cells or photonic gates. With their future evolution threatened by several hardware constrains, including the integration density that can be achieved with current mesh topologies, in this work, we present a unit cell topology design to increase the integration density of waveguide mesh arrangements based on folded Mach-Zehnder Interferometers. We report the design details of a 40-unit cell waveguide mesh integrated in a 11mm x 5.

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Programmable integrated photonic circuits have been called upon to lead a new revolution in information systems by teaming up with high speed digital electronics and in this way, adding unique complementary features supported by their ability to provide bandwidth-unconstrained analog signal processing. Relying on a common hardware implemented by two-dimensional integrated photonic waveguide meshes, they can provide multiple functionalities by suitable programming of their control signals. Scalability, which is essential for increasing functional complexity and integration density, is currently limited by the need to precisely control and configure several hundreds of variables and simultaneously manage multiple configuration actions.

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Photonic integrated circuits based on waveguide meshes and multibeam interferometers call for large-scale integration of Tunable Basic Units (TBUs) that feature beam splitters and waveguides. This units are loaded with phase actuators to provide complex linear processing functionalities based on optical interference and can be reconfigured dynamically. Here, we propose and experimentally demonstrate, to the best of our knowledge, for the first time, a thermally actuated Dual-Drive Directional Coupler (DD-DC) design integrated on a silicon nitride platform.

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Purpose: Citation analysis is one of the most commonly used bibliometric tools for measuring the academic importance of a report in a specific area of knowledge. The objective of the present study was to identify the 100 most cited reports on medication-related osteonecrosis of the jaw (MRONJ), determine their main bibliometric characteristics, and identify the bibliometric variables that affected the citation rates.

Materials And Methods: We performed a data search in the Scopus database to determine the number of MRONJ article citations up to September 30, 2018.

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Correction of maxillary compression via palatal expansion is easy in children and adolescents, but more complicated once growth is finished. This correction may be performed by progressive expansion using orthopaedic appliances after osteotomy with more stable results, which facilitate a second phase to achieve larger expansions. We present a clinical case treated using a customized device that improves predictability.

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Tobacco is one of the leading causes of preventable death in the developed world. Smoking is associated with a large number of oral pathologies, such as cancer and periodontitis. Dental professionals can play a key role in preventing these health problems.

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Objectives: To determine the diagnostic value of diascopy and other non-invasive clinical aids on recent differential diagnosis algorithms of oral mucosal pigmentations affecting subjects of any age.

Material And Methods: Data Sources: this systematic review was conducted by searching PubMed, Scopus, Dentistry & Oral Sciences Source and the Cochrane Library (2000-2015); Study Selection: two reviewers independently selected all types of English articles describing differential diagnosis algorithms of oral pigmentations and checked the references of finally included papers; Data Extraction: one reviewer performed the data extraction and quality assessment based on previously defined fields while the other reviewer checked their validity.

Results: Data Synthesis: eight narrative reviews and one single case report met the inclusion criteria.

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