ORCID Profile
0000-0002-4993-4299
Current Organisations
Technical University of Denmark
,
York University
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Publisher: Springer Science and Business Media LLC
Date: 16-07-2022
DOI: 10.1038/S41467-022-31884-2
Abstract: Today’s optical communication systems are fast approaching their capacity limits in the conventional telecom bands. Opening up new wavelength bands is becoming an appealing solution to the capacity crunch. However, this ordinarily requires the development of optical transceivers for any new wavelength band, which is time-consuming and expensive. Here, we present an on-chip continuous spectral translation method that leverages existing commercial transceivers to unlock the vast and currently unused potential new wavelength bands. The spectral translators are continuous-wave laser pumped aluminum gallium arsenide on insulator (AlGaAsOI) nanowaveguides that provide a continuous conversion bandwidth over an octave. We demonstrate coherent transmission in the 2-μm band using well-developed conventional C-band transmitters and coherent receivers, as an ex le of the potential of the spectral translators that could also unlock communications at other wavelength bands. We demonstrate 318.25-Gbit s −1 Nyquist wavelength- ision multiplexed coherent transmission over a 1.15-km hollow-core fibre using this approach. Our demonstration paves the way for transmitting, detecting, and processing signals at wavelength bands beyond the capability of today’s devices.
Publisher: IOP Publishing
Date: 17-05-2023
Abstract: In its 60 years of existence, the field of nonlinear optics has gained momentum especially over the past two decades thanks to major breakthroughs in material science and technology. In this article, we present a new set of data tables listing nonlinear-optical properties for different material categories as reported in the literature since 2000. The papers included in the data tables are representative experimental works on bulk materials, solvents, 0D–1D–2D materials, metamaterials, fiber waveguiding materials, on-chip waveguiding materials, hybrid waveguiding systems, and materials suitable for nonlinear optics at THz frequencies. In addition to the data tables, we also provide best practices for performing and reporting nonlinear-optical experiments. These best practices underpin the selection process that was used for including papers in the tables. While the tables indeed show strong advancements in the field over the past two decades, we encourage the nonlinear-optics community to implement the identified best practices in future works. This will allow a more adequate comparison, interpretation and use of the published parameters, and as such further stimulate the overall progress in nonlinear-optical science and applications.
Publisher: Informa UK Limited
Date: 02-11-2017
Publisher: AIP Publishing
Date: 10-2019
DOI: 10.1063/1.5115232
Abstract: Wavelength conversion technology is imperative for the future high-speed all-optical network. Nonlinear four-wave mixing (FWM) has been used to demonstrate such functionality in various integrated platforms because of their potential for the realization of a chip-scale, fully integrated wavelength converter. Until now, waveguide-based wavelength conversion on a chip requires a pump power beyond the reach of available on-chip lasers. Although high-quality factor (Q) microresonators can be utilized to enhance the FWM efficiency, their narrow resonance linewidths severely limit the maximal data rate in wavelength conversion. In this work, combining the ultrahigh effective nonlinearity from a high-confinement aluminum gallium arsenide waveguide and field enhancement from a microring resonator with a broad resonance linewidth, we realize all-optical wavelength conversion of a 10-Gbaud data signal by using a pump power, for the first time, at a submilliwatt level. With such a low operation power requirement, a fully integrated high-speed wavelength converter is envisioned for the future all-optical network. The waveguide cross-sectional dimension is engineered in a submicron scale to enhance the light confinement, which pushes the device effective nonlinearity to 720 W−1 m−1 while maintaining a broad operation bandwidth covering the telecom S-, C-, and L-bands. Moreover, we demonstrate that a single microring resonator is capable of handling a high-speed data signal at a baud rate up to 40 Gbit/s. All the wavelength conversion experiments are validated with bit-error rate measurements.
Publisher: BMJ
Date: 20-02-2020
DOI: 10.1136/INJURYPREV-2019-043484
Abstract: Drowning is a leading cause of injury-related mortality globally. Unintentional drowning (International Classification of Diseases (ICD) 10 codes W65-74 and ICD9 E910) is one of the 30 mutually exclusive and collectively exhaustive causes of injury-related mortality in the Global Burden of Disease (GBD) study. This study’s objective is to describe unintentional drowning using GBD estimates from 1990 to 2017. Unintentional drowning from GBD 2017 was estimated for cause-specific mortality and years of life lost (YLLs), age, sex, country, region, Socio-demographic Index (SDI) quintile, and trends from 1990 to 2017. GBD 2017 used standard GBD methods for estimating mortality from drowning. Globally, unintentional drowning mortality decreased by 44.5% between 1990 and 2017, from 531 956 (uncertainty interval (UI): 484 107 to 572 854) to 295 210 (284 493 to 306 187) deaths. Global age-standardised mortality rates decreased 57.4%, from 9.3 (8.5 to 10.0) in 1990 to 4.0 (3.8 to 4.1) per 100 000 per annum in 2017. Unintentional drowning-associated mortality was generally higher in children, males and in low-SDI to middle-SDI countries. China, India, Pakistan and Bangladesh accounted for 51.2% of all drowning deaths in 2017. Oceania was the region with the highest rate of age-standardised YLLs in 2017, with 45 434 (40 850 to 50 539) YLLs per 100 000 across both sexes. There has been a decline in global drowning rates. This study shows that the decline was not consistent across countries. The results reinforce the need for continued and improved policy, prevention and research efforts, with a focus on low- and middle-income countries.
Publisher: Springer Science and Business Media LLC
Date: 16-10-2019
DOI: 10.1038/S41586-019-1545-0
Abstract: Since 2000, many countries have achieved considerable success in improving child survival, but localized progress remains unclear. To inform efforts towards United Nations Sustainable Development Goal 3.2—to end preventable child deaths by 2030—we need consistently estimated data at the subnational level regarding child mortality rates and trends. Here we quantified, for the period 2000–2017, the subnational variation in mortality rates and number of deaths of neonates, infants and children under 5 years of age within 99 low- and middle-income countries using a geostatistical survival model. We estimated that 32% of children under 5 in these countries lived in districts that had attained rates of 25 or fewer child deaths per 1,000 live births by 2017, and that 58% of child deaths between 2000 and 2017 in these countries could have been averted in the absence of geographical inequality. This study enables the identification of high-mortality clusters, patterns of progress and geographical inequalities to inform appropriate investments and implementations that will help to improve the health of all populations.
Publisher: Springer Science and Business Media LLC
Date: 12-2020
DOI: 10.1186/S13031-020-00329-2
Abstract: Rohingya diaspora or Forcibly Displaced Myanmar Nationals (FDMNs), took shelter in the refugee c s of Cox’s Bazar, Bangladesh due to armed conflict in the Rakhine state of Myanmar. In such humanitarian crises, delivering sexual and reproductive health (SRH) services is critical for better health outcomes of this most-at-risk population where more than half are adolescent girls and women. This is a reflective paper on challenges and related mitigation strategies to conduct SRH research among FDMNs. The research on which this paper is based employed a concurrent mixed-method design combining a cross-sectional survey and qualitative interviews and group discussions with FDMNs to understand their SRH needs and demand-side barriers. Assessment of health facilities and qualitative interviews with healthcare providers and key stakeholders were carried out to assess facility readiness and supply-side barriers. The researchers faced different challenges while conducting this study due to the unique characteristics of the FDMN population and the location of the refugee c s. The three key challenges researchers encountered include: sensitivity regarding SRH in the FDMNs, identifying appropriate s ling strategies, and community trust issues. The key approaches to overcome these challenges involved: actively engaging community members and gatekeepers in the data collection process to access respondents, identifying sensitive SRH issues through survey and exploring in-depth during qualitative interviews and contextually modifying the s ling strategy. Contextual adaptation of research methods and involving community and local key stakeholders in data collection are the key lessons learnt from this study. Another important lesson was researchers’ identity and positionality as a member of the host country may create distrust and suspicion among the refugees. The multi-level complexities of humanitarian settings may introduce unforeseen challenges and interrupt research plans at different stages of research which require timely and contextual adaptations.
Publisher: Research Square Platform LLC
Date: 20-01-2022
DOI: 10.21203/RS.3.RS-1086400/V1
Abstract: Despite being perceived historically to provide "unlimited" bandwidth, today’s optical communication systems are fast approaching their capacity limits in the conventional telecom bands. To satisfy the ever-increasing capacity demand, opening up new wavelength bands is becoming an appealing solution both in cabled and free-space optical communications in the transparent windows. However, this would ordinarily require the development of whole optical transceivers for any new wavelength band, which is both time-consuming and expensive. Here, we present an on-chip continuous spectral translation based coherent optical communication approach that can exploit existing commercial transceivers to unlock the vast and currently unused potential new wavelength bands rather than dictate the need to develop new coherent transceivers operating directly in those bands. The spectral translators are continuous-wave pumped aluminium gallium arsenide on insulator (AlGaAsOI) nanowaveguides that can provide a continuous conversion bandwidth over an octave. This enables unprecedented coherent transmission in the 2-μm wavelength band using well-developed conventional C-band transmitters and coherent receivers. We demonstrate 318.25-Gbit s -1 Nyquist wavelength- ision multiplexed coherent transmission over a 1.15-km hollow-core fibre in the 2-μm wavelength band using this approach. Our demonstration paves the way for coherently transmitting, detecting, and processing signals at wavelength bands beyond the capability of today’s devices.
Publisher: Optica Publishing Group
Date: 10-02-2020
DOI: 10.1364/OL.383085
Abstract: Exploring new frequency bands for optical transmission is essential to overcome the capacity crunch. The 2-µm band is becoming a research spotlight due to available broadband thulium-doped fiber lifiers as well as low-latency, low-loss hollow-core fibers. Yet most of the 2-µm band devices designed for optical communication are still in their infancy. In this Letter, we propose wavelength conversion based on four-wave mixing in a highly nonlinear AlGaAsOI nanowaveguide to bridge the 2-µm band and the conventional bands. Due to the strong light confinement of the AlGaAsOI nanowaveguide, high-order phase match is enabled by dispersion engineering to achieve a large synergetic conversion bandwidth with high conversion efficiency. Simulation results show a possible conversion bandwidth over an octave. An AlGaAsOI nanowaveguide with 3-mm length and a nominal cross-section dimension of 320 n m × 680 n m is used for the wavelength conversion of a 10 Gbit/s non-return-to-zero on–off keying signal and a 10 Gbit/s Nyquist-shaped four-level pulse- litude modulation signal. A conversion efficiency of − 28 d B is achieved using a 17.5-dBm continuous-wave pump in the C band, with 744 nm conversion from 1999.65 to 1255.35 nm.
Publisher: BMJ
Date: 07-2019
DOI: 10.1136/BMJOPEN-2018-028340
Abstract: Rohingya diaspora are one of the most vulnerable groups seeking refuge in c s of Cox’s Bazar, Bangladesh, arising an acute humanitarian crisis. More than half of the Rohingya refugees are women and adolescent girls requiring quality sexual and reproductive health (SRH) services. Minimum initial service package of SRH are being rendered in the refugee c s however, WHO is aiming to provide integrated comprehensive SRH services to meet the unmet needs of this most vulnerable group. For sustainable and successful implementation of such comprehensive SRH service packages, a critical first step is to undertake a situation analysis and understand the current dimensions and capture the lessons learnt on their SRH-specific needs and implementation challenges. This situation analysis is pertinent in current humanitarian condition and will provide an overview of the needs, availability and delivery of SRH services for adolescent girls and women, barriers in accessing and providing those services in Rohingya refugee c s in Cox’s Bazar, Bangladesh, and similar humanitarian contexts. A concurrent mixed-methods design will be used in this study. A community-based household survey coupled with facility assessments as well as qualitative in-depth interviews, key informant interviews and focus group discussions will be conducted with community people of Rohingya refugee c s and relevant stakeholders providing SRH services to Rohingya population in Cox’s Bazar, Bangladesh. Survey data will be analysed using univariate, bivariate and multivariable regression statistics. Descriptive analysis will be done for facility assessment and thematic analysis will be conducted with qualitative data. Ethical approval from Institutional Review Board of BRAC James P Grant School of Public Health (2018-017-IR) has been obtained. Findings from this research will be disseminated through presentations in local, national and international conferences, workshops, peer-reviewed publications, policy briefs and interactive project report.
Publisher: Walter de Gruyter GmbH
Date: 04-09-2019
DOI: 10.2478/GP-2019-0016
Abstract: The 6 item Kessler Psychological Distress Scale (K6) is a screening tool for psychological distress with robust psychometric properties however, information is lacking on such properties of the scale on its Bangla version. The aim of this study was to evaluate the psychometric properties of the Bangla version of the K6 scale in young people. A self-administered questionnaire survey was conducted between August 2017 and April 2018 among 718 students aged 13-24 years (45% females) from Dhaka, Bangladesh. Psychological distress was assessed using the Bangla K6. The survey was repeated in a week. Statistical software AMOS 25 and Stata SE 14 were used to conduct the analyses. The Bangla K6 scale demonstrated an acceptable internal consistency with high Cronbach alpha. Principal component analysis confirmed a single-factor structure of the scale. Confirmatory factor analysis supported the one-factor structure of the scale with adequate fit to the survey data. Test-retest reliability was acceptable with good reliability coefficients. Receiver operating characteristic analyses showed good prediction of depressive symptoms by the Bangla K6 scores. This study provides an initial support for the Bangla K6 scale as an acceptable instrument to assess psychological distress of Bangla-speaking young people. More research is needed to understand our ability to identify vulnerable in iduals, whose native language is Bangla and who are in need of mental health support.
Location: Bangladesh
Location: Bangladesh
No related grants have been discovered for Minhao Pu.