bluuebunny/crossref_metadata_2025 huggingface dataset:
Reconstruction of Cymodocea nodosa’s dynamics as a tool to examine the conservation status of a Mediterranean declared marine protected area
Authors: BOUTAHAR LOUBNA , ESPINOSA FREE , BAZAIRI HOCEIN
Published: September 2022

Seagrass habitats rank amongst the most valuable ecosystems in the biosphere. They support fisheries production, climate change mitigation, water quality improvement, and coastal protection. Faced with the current global crisis of accelerating losses of this key component of coastal environments, strong efforts have been expended within the conservation movement to flatten their decline curve. Although understanding the functioning of seagrass ecosystems and how they respond to stressors has improved over the last years, major gaps exist for West Africa including basic ecological and distributional knowledge. This study aimed to investigate, for the first time, the structural development and dynamics of two Cymodocea nodosa meadows in Al Hoceima National Park (the unique official marine protected area of the Mediterranean Moroccan coast) using the reconstruction techniques as an indirect measurement of seagrass growth. C. nodosa’s leaves were remarkably invaded by epiphytes while leaf production, shoot density, above and belowground biomass, and vertical and horizontal rhizome elongation were in the lowest recorded values. Shoot age structure showed that since the second-year class, the survival rate of shoots has decreased. Regarding the severely slow recruitment rates, the populations’ net growths declined. Besides this negative growth trend, CymoSkewm biotic index assigned a slightly polluted ecological status to both meadows. The seagrass faces numerous pressures, mainly fishing by trawling and alien species invasion. The primary conservation challenge for C. nodosa of Al Hoceima National Park is ensuring that this marine protected area becomes operationally implemented and actively managed. Until then, the seagrass habitat-forming species is not safeguarded.
Biochemical composition, nutritional value and socio-economic impacts of the invasive crab Callinectes sapidus Rathbun, 1896 in central Mediterranean Sea
Authors: Khamassi Faten , Rjiba Bahri Wafa , Mnari Bhouri Amira , Chaffai Amani , Soufi kechaou Emna , Ghanem Raouia , Ben Souissi Jamila
Published: September 2022

The Atlantic crab Callinectes sapidus was recently recorded in Tunisia and presents an invasive behavior. This study aims to evaluate its socio-economic impacts on small-scale fisheries and to analyze variations in chemical composition, fatty acids profile, and nutritive value according to sex and edible tissues. Socio-economic surveys via face-to-face revealed a decline in fishermen’s income from 15% to even 70% (damages on fishing nets and catches). Muscles yield of Callinectes sapidus ranged between 36.07±2.84% and 42.83±6.53% respectively for females and males. All the analyzed tissues contained high protein contents (> 23%) and particularly cephalothorax muscles reaching 27.05±0.16%. This new exotic food can be recommended in low fat diets since it contained less than 5% of total fats. The fatty acid profile was dominated by the polyunsaturated fatty acids (PUFA) for both sexes and all the analyzed tissues. Eicosapentaenoic acid, docosahexaenoic acid and arachidonic acid were the most abundant PUFA in all tissues ranging respectively from 9.31% to 15.64%, from 8.74% to 13.78% and between 6.81% and 9.21%. All the nutritional indexes of lipids indicated that this crab could be beneficial for human health. In addition, it constitutes a new marine resource with high economic opportunity.
Ethical consumption: why should we understand it as a social practice within a multilevel framework?
Authors: Karimzadeh Sara , Boström Magnus
Published: September 2022

This article discusses the importance of a multilevel and intertwined understanding of ethical consumption given its conjunction with other social practices. Although the literature on ethical consumption is vast, the role of sociotechnical regimes including technological and cultural elements, infrastructure, market and regulation has been mainly overlooked in this literature. This may be so because ethical consumption practices that refer to other-oriented consumption practices are mainly considered in the view of the motivations and preferences of individual consumers. Due to the insufficiency of individualistic approaches to explain stimulators and inhibitors of ethical consumption, there might be other components in society to lead (un)ethical consumption decisions. Therefore, to avoid an oversimplified view of ethical consumption, this paper contributes with a theoretical discussion on combining social practice theory (SPT) with a multi-level perspective (MLP). Although the SPT is a very well-structured framework in consumption studies, the necessity of a combined approach concerns the often-insufficient attention paid to structural prerequisites of various consumption forms in social practice theories. By understanding ethical consumption practices according to a multi-level framework, the paper emphasizes the importance of structural factors at macro- and mesolevels. It also contributes attention to how ethical consumption grows due to dialectical processes between levels, showing that niche practices can, at the same time, both challenge and depend on existing regimes.
Study protocol: The clinical features, epidemiology, and causes of paediatric encephalitis in southern Vietnam
Authors: Huong Nguyen Hoang Thien , Toan Nguyen Duc , Quy Du Tuan , Khanh Truong Huu , Thinh Le Quoc , Nhan Le Nguyen Thanh , Minh Ngo Ngoc Quang , Turner Hugo , Thwaites Louise , Irani Sarosh , Hung Nguyen Thanh , Tan Le Van
Published: September 2022

Encephalitis is a major cause of morbidity and mortality worldwide. The clinical syndrome of encephalitis consists of altered mental status, seizures, neurologic signs, and is often accompanied by fever, headache, nausea, and vomiting. The encephalitis in children has been known that more common than in adult, with the incidence rate of infants was 3.9 times higher than that of people 20-44 years of age. The reported incidence of hospitalization attributed to paediatric encephalitis ranged from 3 to 13 admissions per 100,000 children per year with the overall mortality ranging from 0 to 7%. There are however more than 100 pathogens that can cause encephalitis and accurate diagnosis is challenging. Over 50% of patients with encephalitis are left undiagnosed despite extensive laboratory investigations. Furthermore, recent studies in high-income settings have suggested autoimmune encephalitis has now surpassed infectious aetiologies, mainly due to increased awareness and diagnostic capacity, which further challenges routine diagnosis and clinical management, especially in developing countries.

There are limited contemporary data on the causes of encephalitis in children in Vietnam. Improving our knowledge of the causative agents of encephalitis in this resource-constrained setting remains critical to informing case management, resource distribution and vaccination strategy. Therefore, we conduct a prospective observational study to characterise the clinical, microbiological, and epidemiological features of encephalitis in a major children’s hospital in southern Vietnam. Admission clinical samples will be collected alongside meta clinical data and from each study participants. A combination of classical assays (serology and PCR) and metagenomic next-generation sequencing will used to identify the causative agents. Undiagnosed patients with clinical presentations compatible with autoimmune encephalitis will then be tested for common forms of the disease. Finally, using direct- and indirect costs, we will estimate the economic burden of hospitalization and seven days post hospital discharge of paediatric encephalitis in our setting.
The use of artificial intelligence in nephrology
Authors: Buczek Weronika , Wiśniewski Mikołaj , Oleszczuk Rafał , Kozińska Iga , Orczykowski Maciej
Published: September 2022

Introduction and methods

Artificial Intelligence(AI) is a relatively new branch of science that studies the display of intelligent behavior by machines and its use in advanced analysis and computation. Due to the potential use of AI, it has also been introduced into medicine and nephrology.

The following article is an analysis of the current knowledge on the potential of AI in nephrology and its relevance to clinicians based on the latest publications contained in the PubMed and Google Scholar databases.

Stage of knowledge

AI found its application in the prognosis of the development of IgA nephropathy thanks to the use of a neural network, which by analyzing the results of research and the drugs used in a large group of patients has learned to detect patients at high risk of developing severe complications at the beginning of the disease. What is more, AI makes it possible to detect DKD earlier and delay renal replacement therapy. In patients undergoing hemodialysis, artificial intelligence developed a model that calculated the appropriate duration of the procedure and adjusted drugs to control blood pressure. Another example of the use of AI is its use in relation to patients undergoing kidney transplantation. The AI calculates the beneficial concentration of an immunosuppressive drug specifically for a given patient, which allows clinicians to limit adverse effects.

Summary

AI is a breakthrough technology that is constantly being developed. Despite the high cost of implementing this technology, it is believed that it could represent the future of medicine and be a new way in treatment techniques and in the early detection of diseases in nephrology.
The usage of botulinum in the treatment of masticatory muscles hyperactivity
Authors: Drożak Martyna , Grabowy Paulina , Drożak Paulina
Published: September 2022

Introduction and purpose: Masticatory muscles hyperactivity is currently a very common problem among adult population. The ignorance of the symptoms and the lack or unsuccessful treatment may lead to serious health complications, which lead to major focus on improvement of the standard therapy for bruxism. The aim of the study was to provide a broad review on the promising treatment of bruxism symptoms with botulinum neurotoxin injections.
Material and method: The review was conducted based on an available literature on PubMed database, searching the following phrases: bruxism, botulinum neurotoxin.
Results: As bruxism has a very complex etiology, the treatment can not be narrowed down to one therapy system. Despite the fact that botulinum neurotoxin injections can not solve the primary reason of bruxism occurrence, it has shown excellent results in treatment of symptoms, since the substance has an ability to induce muscle relaxation. Therefore, such pain relief substance has shown a much better performance and long lasting results in comparison to drug therapy or behavioral treatment.
Conclusions: The research confirmed that the usage of botulinum in the treatment of masticatory muscles hyperactivity is safe, well-tolerated by the patients and shows satisfying results. Conducted studies have proven that the most effective way of bruxism treatment is a therapy, which tackles both complex etiology of the disorder and its symptoms.
A REVIEW OF FUTURE TRENDS IN 3-D PRINTING OF ARMAMENT AND EXPLOSIVE DEVICES
Authors: KUMAR DINESH , PAL BALKISHAN , KUMAR BALWINDER , BHARDWAJ VIKAS
Published: September 2022

Advances in Computer aided design (CAD), modeling and Three-dimensional (3D) printing has led to paradigm shift in development of innovative and miniaturized explosive devices for armament applications. In conventional techniques, explosives are either pressed or casted and machined to required geometry. These conventional processes are mostly manual and monotonous; require high-cost tooling and the lead-time from concept to product is high. 3D printing is an automated additive manufacturing process in which the material is deposited layer-by-layer to build physical part with any intricate geometry and profile, from the CAD model of the part. 3D printing of explosive devices offers advantages of computer aided design techniques, automation, direct physical part fabrication, low lead-time, low cost and any geometrical shape can be printed. It also offers advantage of printing explosive parts in the battlefields. In this paper, along with the detailed review of future trends in 3D printing of armament and explosive devices, a case study of 3D printing of plastic bullets in Acrylonitrile Butadiene Styrene (ABS) material is presented. The plastic bullets are used in low intensity conflicts and riot control. The experimental firing trials were conducted using standard AK- 47 gun firing on Gelatin target blocks placed at 30 m distance from the muzzle of the gun. The trials showed performance of ABS bullets in terms of lethality and velocity drop comparable to existing plastic bullets made of Nylon-66 manufactured by injection molding process. 3D printed ABS bullets have advantage of batch-to-batch repeatability, high accuracy. 3D printing is revolutionizing the way armament and explosive devices are manufactured, performance improvement and miniaturization.
ELECTROMAGNETIC RAIL GUN FRAGMENT ACCELERATOR CONCEPT DEMONSTRATOR
Authors: SEQUEIRA JOSE
Published: September 2022

The future objective of this study is to establish testing techniques to evaluate the penetrating ability of shrapnel fragments produced from fragmenting warheads. Difficult to capture data points such as residual velocity and mass are required to, individually, characterise single fragment penetrability. One of the more challenging aspects of penetrability testing is the ability to study individual fragment impact at speeds exceeding 2 km/s. Fragment acceleration by means of an electromagnetic (EM) rail gun seems to be well suited to test weapon applications and is expected to be the future system of choice for high velocity fragment impact analysis. A concept-demonstrator rail gun (6000J, Ma MV 320 m/s) and internal ballistic model is presented in this study establishing technology toward the future development of a full-scale EM fragment accelerator test system. This paper presents the findings and challenges encountered during the development and testing of small-scale electromagnetic rail gun. In particular, findings are presented onunexpectedforward plasma escape likely resulting from excessive joule heating in the armature-railinjection region.
Augmenting Markov Cohort Analysis to Compute (Co)Variances: Implications for Strength of Cost-Effectiveness
Authors: Hazen Gordon B.
Published: September 2022

Markov cohort analysis is a popular deterministic method in medical decision making for calculating mean outcomes in a Markov model by following a cohort of individuals through time. At present, obtaining outcome variances requires either forsaking cohort analysis in favor of a Markov decision process model or using Monte Carlo simulation (microsimulation), a more computationally demanding procedure that provides only statistical estimates. Here we derive an augmented version of cohort analysis that allows exact computation (not merely estimation) of (co)variances. In second-order models that incorporate parameter uncertainty, augmented cohort analysis can replace the “inner loop” required in Monte Carlo simulation, resulting in quicker and more accurate estimates.

One reason for computing variances is to calculate a measure of the strength of an affirmative cost-effectiveness conclusion. In Markov cost-effectiveness analysis, an equivalent measure of cost-effectiveness is positivity of the expected incremental net monetary benefit. Augmented cohort analysis allows calculation of the number of standard deviations that this quantity falls above zero. As a measure of strength of cost-effectiveness, this quantity increases with cohort size. This means that the common practice of taking cohort size to be one can substantially underestimate the strength of a resulting cost-effectiveness conclusion under realistically large cohorts. Moreover, if realistic cohort size is large, then modelers can avoid microsimulation by using augmented cohort analysis and Chebyshev bounds to guarantee the probability of cost effectiveness is close to one.

History: Accepted by J. Paul Brooks, Area Editor for Applications in Biology, Medicine, & Healthcare.

Supplemental Material: The online appendix is available at https://doi.org/10.1287/ijoc.2022.1234 .
Toxicology in the emergency department: what's new?
Authors: Motohashi Kenzo , Thanacoody Ruben HK
Published: September 2022

Intentional and accidental drug overdose, recreational drug use and exposure to toxic substances are common reasons for people presenting to emergency departments. Although the mortality rate associated with these presentations is low in the UK, they can lead to significant morbidity and prolonged hospital admissions.

This review discusses new developments in the management of paracetamol overdose. Several new protocols for the infusion of acetylcysteine, the antidote for paracetamol overdose, have been proposed in the past decade and evaluated in clinical studies. The 12-hour Scottish and Newcastle Acetylcysteine Protocol regimen and 20-hour Australian two-infusion bag protocol have been widely adopted into clinical practice and endorsed in national guidelines because of their shorter duration, reduction in adverse effects and efficacy in treating overdose. This article includes a care pathway that can facilitate the implementation of the Scottish and Newcastle Acetylcysteine Protocol.

This article also discusses the emergency management of ingested button batteries, describes the emerging threat of novel psychoactive substances, and provides an update on new UK antidote guidelines. Further up-to-date guidance on management of clinical toxicology is available to healthcare professionals on the internet database TOXBASE.
Coress is an independent charity, supported by AXA Health, the MDU and the WPA Benevolent Foundation
Authors: Smith Frank CT
Published: September 2022

We are grateful to those who have provided the material for these reports. The online reporting form is available on the website ( www.coress.org.uk ), which also includes previous Feedback reports. Published cases will be acknowledged by a Certificate of Contribution, which may be included in the contributor's record of continuing professional development, or which may form part of appraisal or annual review of competence progression (ARCP) portfolio documentation. Trainee contributions are particularly welcome.
The ASiT/RCS England Foundation Doctor Essay Prize winning submission
Authors: Albastaki O
Published: September 2022

An account of juggling a surgical career with a family life and how different health services are in the UK and Dubai: read the ASiT/RCS England Foundation Doctor winning submission here, as well as a statement about the Parents in Surgery network at RCS England and how it can support surgeons.
Charging overseas visitors
Authors: Wheeler Robert
Published: September 2022

Our legal contributor looks at how patients who are ‘not ordinarily resident’ in the UK are charged for treatment.
Is the glass half full or half empty?
Authors: Mortensen Neil
Published: September 2022

The President looks at how we can remain optimistic in the face of increasing challenges in training, especially in the wake of the pandemic and increasing surgical waiting lists.
Care and consumption
Authors: Godin Laurence
Published: September 2022

In this article, I argue that care is a useful tool to think about consumption as embedded in social relations within and outside the market, and draw the consequences for moving towards sustainable lifestyles. To do so, I engage in a review of the literature that brings together consumption and care in its various forms. I review three main bodies of work: the literature on consumption that links care to consumer behaviour and consumption practices; the work addressing the commodifications of care and how it feeds in the neoliberal organisation of society; and the literature on climate change and the development of sustainable lifestyles. I close with a reflection on some lessons of care for academic researchers studying sustainability, consumption and a transition towards more sustainable and just societies.
VIS-NIR superachromatic triplet design with five-color correction for a
broadband interferometer
Authors: Lu Qi , Ding Yifan , Wang Wei , Liu Shijie , Xu Min
Published: September 2022

In general,

k

lenses with different materials can achieve at most (

k

+

1

) color correction (

k
≥
2

). A superachromat containing three lenses is designed to achieve five-color correction in the 600–1600 nm waveband, where the maximum chromatic focal shift is controlled within 1/100,000 of the focal length, achieving an almost unprecedented result. Conditions for lens power combination of three thin lenses in contact are first derived based on the Buchdahl dispersion equation; then a metric is introduced to verify the five-color correction, and a correction method is proposed to improve the refractive index fitting accuracy of the Buchdahl model from

∼

10

−
3

to

∼

10

−
7

. By traversing 197 ecofriendly glass materials in the CDGM glass library iteratively, 113 initial structures are obtained in only 61.75 s, from which the structure with the minimum chromatic focal shift is selected to be optimized with Opticstudio. By setting up required operands, the final structure being within the diffraction limit in a field of view of

±

0.05

∘

is obtained within only 6 s, where the maximum longitudinal chromatic aberration is close to the maximum chromatic focal shift. We provide a complete theoretical basis and important guidance for designing broadband superachromats with (

k

+

2

) color correction using only

k

lenses and the smallest chromatic focal shift, and based on the theories, we have developed a broadband interferometer.
Wavelet denoising approach in long-distance optical communications
Authors: Wang Qiang , Cui Lei , Wang Xuewei , Ma Jing , Tan Liying , Wang Hui
Published: September 2022

For free-space optical communication links, the light spot collected by the photodetector at the receiving terminal is not an ideal light spot that is affected by atmospheric turbulence. The light spot collected by the photodetector will also be accompanied by various noises. More importantly, the presence of all noise will bring errors to acquire the light spot’s center. As a result, the tracking error can affect the stability of the optoelectronic tracking system. Therefore, it is necessary to remove noise from the collected images. The method of removing noise needs to be effective, but it cannot bring a large amount of calculation to affect the real-time performance. The calculation amount of wavelet transform is small, and the effect of noise removal is better, which can focus on local details with arbitrary expansion coefficients. An improved wavelet denoising method is proposed. The long-distance verification experiment (11.16 km) verified the effectiveness of this approach, compared with the traditional method. Furthermore, to the best of our knowledge, this new approach would be beneficial for the design of optical communication systems.
Utilizing broadband wavelength-division multiplexing capabilities of hollow-core fiber for quantum communications
Authors: Nasti Umberto , Sakr Hesham , Davidson Ian A. , Poletti Francesco , Donaldson Ross J.
Published: September 2022

One of the major challenges in the deployment of quantum communications (QC) over solid-core silica optical fiber is the performance degradation due to the optical noise generated with co-propagating classical optical signals. To reduce the impact of the optical noise, research teams are turning to new and novel architectures of solid-core and hollow-core optical fiber. We studied the impact when co-propagating a single-photon level (850 nm) and two classical optical signals (940 nm and 1550 nm) while utilizing a nested antiresonant nodeless fiber (NANF) with two low-loss windows. The 940 nm signal was shown to impact the single-photon measurement due to the silicon detector technology implemented; however, multiplexing techniques and filtering could reduce the impact. The 1550 nm signal was shown to have no detrimental impact. The results highlight that both high bandwidth optical traffic at 1550 nm and a QC channel at 850 nm could co-propagate without degradation to the QC channel.
Fast physical random bit generation based on a chaotic optical injection system with multi-path optical feedback
Authors: Cui Bing , Xia Guangqiong , Tang Xi , Wang Yongbo , Wu Zhengmao
Published: September 2022

Based on the chaotic signal provided by a simple chaotic system, a random bit sequence with a rate of 640 Gb/s is generated through adopting the circulating exclusive-or (CXOR) post-processing method. Such a simple chaotic system is built via a slave semiconductor laser subject to optical injection of a chaotic signal originated from a master semiconductor laser under multi-path optical feedback. First, through inspecting the dependences of the time-delay-signature (TDS) and bandwidth of the chaotic signal on some key operation parameters, optimized parameters are determined for generating a high-quality chaotic signal with a large bandwidth and low TDS. Second, the high-quality chaotic signal is converted to an 8-bit digital signal by sampling with a digital oscilloscope at 80 GSa/s. Next, through adopting the CXOR post-processing method, a bit sequence with a rate of 640 Gb/s is obtained. Finally, the randomness is estimated by the National Institute of Standard Technology (NIST) Special Publication 800-22 statistical tests, and the results demonstrate that the obtained random bit sequence can pass all the NIST tests.
RobustPPG: camera-based robust heart rate estimation using motion cancellation
Authors: Maity Akash Kumar , Wang Jian , Sabharwal Ashutosh , Nayar Shree K.
Published: September 2022

Camera-based heart rate measurement is becoming an attractive option as a non-contact modality for continuous remote health and engagement monitoring. However, reliable heart rate extraction from camera-based measurement is challenging in realistic scenarios, especially when the subject is moving. In this work, we develop a motion-robust algorithm, labeled RobustPPG, for extracting photoplethysmography signals (PPG) from face video and estimating the heart rate. Our key innovation is to explicitly model and generate motion distortions due to the movements of the person’s face. We use inverse rendering to obtain the 3D shape and albedo of the face and environment lighting from video frames and then render the human face for each frame. The rendered face is similar to the original face but does not contain the heart rate signal; facial movements alone cause pixel intensity variation in the generated video frames. Finally, we use the generated motion distortion to filter the motion-induced measurements. We demonstrate that our approach performs better than the state-of-the-art methods in extracting a clean blood volume signal with over 2 dB signal quality improvement and 30% improvement in RMSE of estimated heart rate in intense motion scenarios.
Short Pulse Mid-IR Fiber Lasers for Advanced Applications in Industry and Science
Authors: Robichaud Louis-Rafaël , Duval Simon
Published: September 2022

We report our latest development on short pulse mid-infrared fiber lasers both at the laser and application level. We will provide an overview of promising applications enabled by mid-IR short pulses in industry and science.
CLONETS-DS – Clock Network Services-Design Study Strategy and Innovation for Clock Services over Optical Fibre
Authors: Vojtěch Josef , Altmannová Lada , Smotlacha Vladimír , Velc Radek , Vohnout Rudolf , Schnatz Harald , Liebisch Tara Cubel , Capone Vincenzo , Chiotis Tryfon , Roberts Guy , Vicinanza Domenico , Binczewski Artur , Bogacki Wojbor , Turza Krzysztof , Pottie Paul-Eric , Tuckey Philip , Calonico Davide , Clivati Cecilia , Curri Vittorio , Holzwarth Ronald , Sprenger Benjamin , Číp Ondřej , Pravdová Lenka , Řeřucha Šimon , Alonso Javier Díaz , Vidal Eduardo Ros , García Trinidad , Rat Benoit , Kodet Jan , Schreiber Ulrich , Kusche Jürgen , Meschede Dieter , Schröder Stefan , Stellmer Simon , Nogas Pawel , Urbaniak Robert , Krehlik Przemysław , Śliwczyński Łukasz , Amy-Klein Anne , Chardonnet Christian , Quintin Nicolas , Seeds Alwyn , Desruelle Bruno , Lautier-Gaud Jean , Ménoret Vincent , Rabault Martin
Published: September 2022

Long-distance time and frequency transfer methods based on optical fibre links attractive both for very high-performance applications and also for many industrial and societal applications, and they complement and offer an alternative to radio- and satellite-based methods.
Large mode area waveguide for silicon photonics and modelocked lasers
Authors: Singh Neetesh , Frare Bruno L. Segat , Bradley Jonathan D. B. , Kärtner Franz X.
Published: September 2022

We show experimental results on large mode area waveguides in silicon photonics. Mode area up to 30 μm2 is demonstrated in a 10 cm long serpentine waveguide with 0.75 dB/cm propagation loss limited only by the aluminum oxide film loss.
Optical limiters relying on VO2 phase transition in thin multilayer films
Authors: Gandolfi Marco , Tognazzi Andrea , Li Bohan , Morales Rocio Camacho , Ambrosio Gina , Baratto Camilla , de Ceglia Domenico , Neshev Dragomir N. , De Angelis Costantino
Published: September 2022

We propose a self-activating optical limiter device based on phase transition of vanadium dioxide in thin multilayer films. The optimal geometry reduces the transmitted power by ~ 70% and shows a recovery time of 10 ns.
Vertical 2D Grating Coupler for Efficient Multiplexing of Six Modes Between the Few Mode Fiber and SOI Chip
Authors: Hsu Yi-Jang , Hsu Shi-Chieh , Lai Yinchieh
Published: September 2022

We have successfully designed a vertical 2D grating coupler that can multiplex/de-multiplex three spatial fiber modes in both polarizations between a few mode fiber and six SOI waveguides with reasonably equalized high efficiencies.
Simultaneous detection of the sign and magnitude of the Poincaré Hopf index of the electromagnetic Gaussian Schell model polarization singular vector beams
Authors: Manisha  , Joshi Stuti , Khan Saba N , Kanseri B. , Senthilkumaran P
Published: September 2022

We report a method to determine the sign as well as the magnitude of the Poincaré Hopf index (PHI) of electromagnetic Gaussian Schell model (EGSM) polarization singular vector beams. This method is based on the analysis of the orientation angle (OA) of polarization. OA distribution is found to form petal like structure around the singularity. The sign and magnitude of PHI are related to the number and the orientation direction of petals around the singularity.
Graphene-based active tunable mode splitting in an indirectly coupled photonic crystal nanobeam cavity–waveguide system
Authors: Ma Jun , Deng Chao-Sheng , Lin Qi , Wang Ling-Ling
Published: September 2022

We propose an indirectly coupled photonic crystal nanobeam (PCN) cavity–waveguide system that consists of two PCN cavities indirectly coupled to each other through a bus waveguide and numerically investigate the mode splitting phenomenon by varying the coupling strength between two cavities. By placing graphene sheets on top of one of the cavities and tuning the Fermi level of graphene, the active control of the mode splitting is achieved without reoptimizing or readjusting the structures. A theoretical model based on the coupled mode theory is further exploited to unveil the physical mechanism behind such a graphene-based active tunable mode splitting phenomenon. Furthermore, active modulation of the group delay is also demonstrated by changing the Fermi level of graphene, achieving a well-controlled slow light effect. Our proposed system is expected to provide a broad range of photonics applications in slow light devices, optical switching, monitoring, and optical sensing.
Security analysis for a mutually partially unbiased bases–based protocol
Authors: Chang Zehong , Wang Fumin , Jia Junliang , Wang Xiaoli , Lv Yi , Zhang Pei
Published: September 2022

The recently proposed mutually partially unbiased bases (MPUB)–based protocol, which encodes with Laguerre–Gaussian modes and Hermite–Gaussian modes of the same mode order, can close the security loophole caused by state-dependent diffraction. However, its pessimistic security proof limits the performance, and some practical issues, such as finite-key size and imperfect sources, have not been considered. Here, we improve the key rates of the MPUB-based protocol by accurately estimating the phase error rate. Moreover, the effect of finite-key size and its performance when combined with the decoy state method are demonstrated. Our work broadens the application scope of the MPUB-based protocol, and thereby advances the development of high-dimensional quantum key distribution using spatial modes.
StarLight: a photonic neural network accelerator featuring a hybrid mode-wavelength division multiplexing and photonic nonvolatile memory
Authors: Guo Pengxing , Zhou Niujie , Hou Weigang , Guo Lei
Published: September 2022

This paper proposes StarLight, a low-power consumption and high inference throughput photonic artificial neural network (ANN) accelerator featuring the photonic ‘in-memory’ computing and hybrid mode-wavelength division multiplexing (MDM-WDM) technologies. Specifically, StarLight uses nanophotonic non-volatile memory and passive microring resonators (MRs) to form a photonic dot-produce engine, achieving optical ‘in-memory’ multiplication operation with near-zero power consumption during the inference phase. Furthermore, we design an on-chip wavelength and mode hybrid multiplexing module and scheme to increase the computational parallelism. As a proof of concept, a 4×4×4 optical computing unit featuring 4-wavelength and 4-mode is simulated with 10 Gbps, 15 Gbps and 20 Gbps data rates. We also implemented a simulation on the Iris dataset classification and achieved an inference accuracy of 96%, which is entirely consistent with the classification accuracy on a 64-bit computer. Therefore, StarLight holds promise for realizing low energy consumption hardware accelerators to address the incoming challenges of data-intensive artificial intelligence (AI) applications.
Entanglement distribution using a biphoton frequency comb compatible with DWDM technology
Authors: Fujimoto Rintaro , Yamazaki Tomohiro , Kobayashi Toshiki , Miki Shigehito , China Fumihiro , Terai Hirotaka , Ikuta Rikizo , Yamamoto Takashi
Published: September 2022

We demonstrate a distribution of frequency-multiplexed polarization-entangled photon pairs over 16 frequency channels using demultiplexers for the signal and idler photons with a frequency spacing of 25 GHz, which is compatible with dense wavelength division multiplexing (DWDM) technology. Unlike conventional frequency-multiplexed photon-pair distribution by a broadband spontaneous parametric down-conversion (SPDC) process, we use photon pairs produced as a biphoton frequency comb by SPDC inside a cavity where one of the paired photons is confined. Owing to the free spectral range of 12.5 GHz and the finesse of over 10 of the cavity, the generated photons having a narrow linewidth in one channel are separated well from those in the other channels, which minimizes channel cross-talk in advance. The observed fidelities of the photon pairs range from 81 % to 96 % in the 16 channels. The results show the usefulness of the polarization-entangled biphoton frequency comb for frequency-multiplexed entanglement distribution via a DWDM system.
Fast and accurate measurement of the polarization-dependent detection efficiency of superconducting nanowire single photon detectors
Authors: Fei Yue , Ji Tianhao , Zhang Labao , Zhu Guanghao , Tan Jingrou , Lv Jiayu , Chen Qi , He Guanglong , Li Feiyan , Wang Xiaohan , Li Hui , Guan Yanqiu , Yin Rui , Wang Hao , Jia Xiaoqing , Zhao Qingyuan , Tu Xuecou , Kang Lin , Chen Jian , Wu Peiheng
Published: September 2022

Superconducting nanowire single photon detectors (SNSPDs) have been extensively investigated due to their superior characteristics, including high system detection efficiency, low dark count rate and short recovery time. The polarization sensitivity introduced by the meandering-type superconductor nanowires is an intrinsic property of SNSPD, which is normally measured by sweeping hundreds of points on the Poincaré sphere to overcome the unknown birefringent problem of the SNSPD’s delivery fiber. In this paper, we propose an alternative method to characterize the optical absorptance of SNSPDs, without sweeping hundreds of points on the Poincaré sphere. It is shown theoretically that measurements on the system detection efficiencies (SDEs) subject to cases of four specific photon polarization states are sufficient to reveal the two eigen-absorptances of the SNSPD. We validate the proposed method by comparing the measured detection spectra with the spectra attained from sweeping points on the Poincaré sphere and the simulated absorption spectra.
System impact and calibration method of power imbalances for a dual-polarization in-phase/quadrature optical transmitter
Authors: Li Si-Ao , Zhang Runzhou , Pan Zhongqi , Yue Yang
Published: September 2022

For the latest 400-Gb/s or upcoming 1-Tb/s single-carrier optical fiber communications systems, dual-polarization quadrature amplitude modulation (DP-QAM) based on in-phase (I) and quadrature (Q) optical transmitter is the only possible solution. In a coherent DP-IQ transmitter, the power difference between the I and Q branches or orthogonally polarized (X and Y) channels are known as the IQ or XY power imbalance, respectively. Uncompensated IQ and XY power imbalances are always troublesome and can significantly limit the performance in long-haul transmission. In this work, we first experimentally investigate the impact of IQ and XY power imbalances on various QAM formats and baud rates in high-speed transmission. A DP-16-QAM up to 86 GBd is investigated, aiming for beyond 400 Gb/s applications. Then, a convenient pre-calibration method based on optical interference is proposed and experimentally demonstrated to detect and compensate both the IQ and XY power imbalances. This method can use the existing modulator structure and low-speed photodiode in the DP-IQ transmitter to obtain the optical interference power by injecting a specific coded electrical signal. After adjusting the time skew of each channel, the power imbalance between two channels can be calibrated by minimizing the optical interference power. The results fit well with the given theoretical analysis, and the proposed technique can be adopted to the DP-IQ transmitter with different QAM formats.
Pulse compression of a single-frequency Q-switched fiber laser based on the cascaded four-wave mixing effect
Authors: Huang Chengzi , Zhao Qilai , Yang Changsheng , Lin Wei , Sun Yuxing , Huang Jiamin , Jiang Kui , Jiang Wanpeng , Feng Zhouming , Zhang Qinyuan , Yang Zhongmin , Xu Shanhui
Published: September 2022

A pulse compressing technology of single-frequency Q-switched laser based on the cascaded four-wave mixing (CFWM) effect is demonstrated theoretically and experimentally, for the first time to the best of our knowledge. A theoretical model of the pulse compression is established through deconstructing the pulse duration evolution in the high-order Stokes and anti-Stokes lights of CFWM. A pulse compression ratio of (2|m|+1)1/2 is quantificationally obtained with m corresponding to the order number of the CFWM light. Utilizing dual-wavelength (DW) single-frequency Q-switched laser injected into a highly nonlinear fiber (HNLF), the pulse compression and the spectral broadening phenomenon are observed simultaneously. As the order number of the CFWM light increases from 0-order to 3-order, the pulse duration has reduced from 115 ns to 47 ns with a compression ratio of 2.45, which is essentially consistent with the theoretical analysis. The pulse compressing technique by CFWM is conducive to promoting the performance development of the single-frequency Q-switched laser, which can improve the system precision in the Lidar, trace gas detection, and high-precision ranging. Furthermore, this technology based on time-frequency transformation dynamics may be generally applicable to other single-frequency pulsed fiber lasers.
Complete alignment of a KB-mirror system guided by ptychography
Authors: Kahnt Maik , Kalbfleisch Sebastian , Björling Alexander , Malm Erik , Pickworth Louisa , Johansson Ulf
Published: September 2022

We demonstrate how the individual mirrors of a high-quality Kirkpatrick–Baez (KB) mirror system can be aligned to each other to create an optimally focused beam, through minimizing aberrations in the phase of the ptychographically reconstructed pupil function. Different sources of misalignment and the distinctive phase artifacts they create are presented via experimental results from the alignment of the KB mirrors at the NanoMAX diffraction endstation. The catalog of aberration artifacts can be used to easily identify which parameter requires further tuning in the alignment of any KB mirror system.
Intensity-interrogated hot-wire anemometer based on chirp effect of a fiber Bragg grating
Authors: Zhang Jiarui , Tang Yuhan , Xu Pengbai , Xu Ou , Dong Xinyong
Published: September 2022

An intensity-interrogated optical fiber hot-wire anemometer based on the chirp effect of fiber Bragg grating (FBG) is presented. The FBG is coated with a silver film and heated optically by a 1480 nm laser beam, which is coupled into the fiber cladding by a long-period grating (LPG) and absorbed by the silver film to convert to thermal heat. Due to the gradual decrease of laser power along the length of the FBG, a temperature gradient is formed that induces a chirp effect to the FBG. Bandwidth of the FBG’s reflection spectrum is therefore broadened that increases its reflected light power. The chirp rate of the FBG reduces with airflow velocity since the temperature gradient is weakened under the cooling effect of the airflow, resulting in a certain relationship between the reflected power of the FBG and airflow velocity. In the experiment, by detecting the reflected power of the FBG, airflow velocity measurement is achieved successfully with a high sensitivity up to −28.60 µW/(m·s−1) at airflow velocity of 0.1 m/s and a dynamic response time of under one second. The measurement range is up to 0 to 11 m/s. The intensity interrogation scheme of the FBG hot-wire anemometer reduces its cost greatly and makes it a promising solution for airflow velocity measurement in practical applications.
Improving the accuracy of high-repetition-rate LIBS based on laser ablation and scanning parameters optimization
Authors: Li Haochen , Liu Tianyuan , Fu Yuchao , Li Wanxiang , Zhang Meng , Yang Xi , Wang You , Huang Meizhen
Published: September 2022

Laser-induced breakdown spectroscopy system based on high-repetition-rate microchip laser (HR-LIBS) has been widely used in elemental analysis due to its high energy stability, good portability and fast spectral acquisition speed. However, repeated ablation on powder pellets like soil and coal using HR-LIBS system encounters the problem of serious decline in measurement accuracy. In this work, the relationship between laser ablation and scanning parameters, their correlation with spectral intensity, as well as the optimization approach were fundamentally studied. The correlations among the crater overlapping rate, crater depth and spectral intensity were obtained. An HR-LIBS system with microchip laser (4 kHz repetition rate, 100 µJ laser pulse energy) to perform repeated scanning ablation was established. A theoretical model of the ablation crater morphology for repeated scanning ablation was developed. By taking soil pellets as the experimental samples, the linear fitting curves of crater depth and the spectral intensity ratio were established with the R2 of 0.90∼0.99. The experimental results showed that as the crater depth developed during repeated ablation, the Si-normalized spectral intensity decreased, and thus the spectral repeatability decreased. It was found that by optimizing the overlapping rate to form a flat crater bottom, the confinement effect of the crater on the plasma could be avoided. As a result, the spectral repeatability was significantly improved. The relative standard deviation (RSD) of Si-normalized spectral intensity was improved from 5% to 0.6%. Finally, repeated ablation was performed with the optimized overlapping rate on soil pellets. The R2 of calibration curves of Fe, Mg, Ca, and Al were all above 0.993, and the average RSDs were between 0.5% and 1%. This study provides a fast, accurate, and stable method for the analysis of the samples consisting of various materials with high heterogeneity.
Efficient and accurate conversion-gain estimation of a photon-counting image sensor based on the maximum likelihood estimation
Authors: Nakamoto Katsuhiro , Hotaka Hisaya
Published: September 2022

We establish a method for estimating conversion gains of image sensors on the basis of a maximum likelihood estimation, one of the most common and well-established statistical approaches. A numerical simulation indicates the proposed method can evaluate the conversion gain more accurately with less data accumulation than known approaches. We also applied this method to experimental images accumulated under a photon-counting–regime illumination condition by a CMOS image sensor that can distinguish how many photoelectrons are generated in each pixel. Resultantly, the conversion gains were determined with an accuracy of three digits from 1000 observed images, whose number is at most 10 times smaller than that required for achieving a similar accuracy by known gain-estimation methods.
Real-time high-spectral-resolution mid-infrared spectroscopy with a signal-to-noise ratio of ten thousand
Authors: Tani Shuntaro , Sugiyama Kei , Sukegawa Takashi , Sato Tatsuro , Ishizuka Yuya , Taya Soichi , Feng David , Komeda Osamu , Suto Hiroyuki , Saitoh Hiroaki , Kobayashi Yohei
Published: September 2022

We developed a mid-infrared spectroscopy system with high spectral resolution and a high signal-to-noise ratio using an extremely high-order germanium immersion grating. The spectroscopic system covers wavelengths from 3 to 5 µm and has a spectral resolution of 1 GHz with a single-shot bandwidth of 2 THz. We proposed a method of improving the signal-to-noise ratio and achieved a ratio of over 3000 with a data acquisition rate of 125 Hz in the presence of fluctuations in the light source and environment. A signal-to-noise ratio of 10,000 was achieved with 0.1-s integration for 100-µW mid-infrared light.