Evaluation of Beam Quality Study of Arbitrary Beam Profiles from On-Wafer Vertical Cavity Surface Emitting Lasers

Vertical cavity surface emitting lasers (VCSELs) have found mainstream use in data centers and short-haul optical fiber communications. Along with the increase in the capacity of such systems comes an increase in the demand for greater power efficiency. System evaluation now includes an assessment of the energy required for each bit of data, a metric referred to as ‘joules per bit’. One source of loss for VCSELs is coupling loss, which is due to a mismatch in the mode profiles of the VCSELs and the optical fiber into which the VSCEL light is coupled. One way to reduce this loss is to develop single-mode VCSEL devices that are modally matched to optical fiber. Efficient development of these devices requires a technique for rapidly evaluating beam quality. This study investigates the use of a vertically mounted commercial beam profiling system and hardware interface software to quickly evaluate the beam quality of arbitrary beam profiles from on-wafer mounted VCSEL devices. This system captures the beam profile emitted from a VCSEL device at fixed locations along the vertical axis. Each image is evaluated within software along a predetermined axis, and the beam quality, or M2, is calculated according to international standards. This system is quantitatively compared against a commercial software package designed for determining beam quality across a fixed axis

Evaluation of Beam Quality Study of Arbitrary Beam Profiles from On-Wafer Vertical Cavity Surface Emitting Lasers

Vertical cavity surface emitting lasers (VCSELs) have found mainstream use in data centers and short-haul optical fiber communications. Along with the increase in the capacity of such systems comes an increase in the demand for greater power efficiency. System evaluation now includes an assessment of the energy required for each bit of data, a metric referred to as ‘joules per bit’. One source of loss for VCSELs is coupling loss, which is due to a mismatch in the mode profiles of the VCSELs and the optical fiber into which the VSCEL light is coupled. One way to reduce this loss is to develop single-mode VCSEL devices that are modally matched to optical fiber. Efficient development of these devices requires a technique for rapidly evaluating beam quality. This study investigates the use of a vertically mounted commercial beam profiling system and hardware interface software to quickly evaluate the beam quality of arbitrary beam profiles from on-wafer mounted VCSEL devices. This system captures the beam profile emitted from a VCSEL device at fixed locations along the vertical axis. Each image is evaluated within software along a predetermined axis, and the beam quality, or M2, is calculated according to international standards. This system is quantitatively compared against a commercial software package designed for determining beam quality across a fixed axis

Getting aligned on representational alignment

Biological and artificial information processing systems form representations that they can use to categorize, reason, plan, navigate, and make decisions. How can we measure the extent to which the representations formed by these diverse systems agree? Do similarities in representations then translate into similar behavior? How can a system's representations be modified to better match those of another system? These questions pertaining to the study of representational alignment are at the heart of some of the most active research areas in cognitive science, neuroscience, and machine learning. For example, cognitive scientists measure the representational alignment of multiple individuals to identify shared cognitive priors, neuroscientists align fMRI responses from multiple individuals into a shared representational space for group-level analyses, and ML researchers distill knowledge from teacher models into student models by increasing their alignment. Unfortunately, there is limited knowledge transfer between research communities interested in representational alignment, so progress in one field often ends up being rediscovered independently in another. Thus, greater cross-field communication would be advantageous. To improve communication between these fields, we propose a unifying framework that can serve as a common language between researchers studying representational alignment. We survey the literature from all three fields and demonstrate how prior work fits into this framework. Finally, we lay out open problems in representational alignment where progress can benefit all three of these fields. We hope that our work can catalyze cross-disciplinary collaboration and accelerate progress for all communities studying and developing information processing systems. We note that this is a working paper and encourage readers to reach out with their suggestions for future revisions.Comment: Working paper, changes to be made in upcoming revision

Filovirus RefSeq Entries: Evaluation and Selection of Filovirus Type Variants, Type Sequences, and Names

Sequence determination of complete or coding-complete genomes of viruses is becoming common practice for supporting the work of epidemiologists, ecologists, virologists, and taxonomists. Sequencing duration and costs are rapidly decreasing, sequencing hardware is under modification for use by non-experts, and software is constantly being improved to simplify sequence data management and analysis. Thus, analysis of virus disease outbreaks on the molecular level is now feasible, including characterization of the evolution of individual virus populations in single patients over time. The increasing accumulation of sequencing data creates a management problem for the curators of commonly used sequence databases and an entry retrieval problem for end users. Therefore, utilizing the data to their fullest potential will require setting nomenclature and annotation standards for virus isolates and associated genomic sequences. The National Center for Biotechnology Information’s (NCBI’s) RefSeq is a non-redundant, curated database for reference (or type) nucleotide sequence records that supplies source data to numerous other databases. Building on recently proposed templates for filovirus variant naming [ ()////-], we report consensus decisions from a majority of past and currently active filovirus experts on the eight filovirus type variants and isolates to be represented in RefSeq, their final designations, and their associated sequences

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

Beam Quality Factor Analysis for Coherently-Coupled Vertically-Emitting Laser Arrays

We report on a method for determining the beam quality factor (M 2 ) for all or selected lobes of coherently-coupled vertically-emitting laser arrays, such as on-wafer photonic crystal vertical-cavity surface-emitting laser (PhC VCSEL) array

Beam Quality Factor Analysis of On-Wafer Vertical Cavity Surface Emitting Lasers

We report on a method for analyzing the beam quality factor of on-wafer vertical cavity surface emitting lasers (VCSEL) leading to an M 2 min-max for each measured device due to asymmetry in the beam profile