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If similar evolutionary forces maintain intra‐ and interspecific diversity, patterns of diversity at both levels of biological organization can be expected to covary across space. Although this prediction of a positive species‐genetic diversity correlation (SGDC) has been tested for several taxa in natural landscapes, no study has yet evaluated the influence of the community delineation on these SGDCs. In this study, we focused on tropical fishes of the Indo‐Pacific Ocean, using range‐wide single nucleotide polymorphism data for a deep‐sea fish (Etelis coruscans) and species presence data of 4878 Teleostei species. We investigated whether a diversity continuum occurred, for different community delineations (subfamily, family, order and class) and spatial extents, and which processes explained these diversity patterns. We found no association between genetic diversity and species richness (α‐SGDC), regardless of the community and spatial extent. In contrast, we evidenced a positive relationship between genetic and species dissimilarities (β‐SGDC) when the community was defined at the subfamily or family level of the species of interest, and when the Western Indian Ocean was excluded. This relationship was related to the imprint of dispersal processes across levels of biological organization in Lutjanidae. However, this positive β‐SGDC was lost when considering higher taxonomic communities and at the scale of the entire Indo‐Pacific, suggesting different responses of populations and communities to evolutionary processes at these scales. This study provides evidence that the taxonomic scale at which communities are defined and the spatial extent are pivotal to better understand the processes shaping diversity across levels of biological organization. [ABSTRACT FROM AUTHOR]

The sex chromosomes have been hypothesized to play a key role in driving adaptation and speciation across many taxa. The reason for this is thought to be the hemizygosity of the heteromorphic part of sex chromosomes in the heterogametic sex, which exposes recessive mutations to natural and sexual selection. The exposure of recessive beneficial mutations increases their rate of fixation on the sex chromosomes, which results in a faster rate of evolution. In addition, genetic incompatibilities between sex‐linked loci are exposed faster in the genomic background of hybrids of divergent lineages, which makes sex chromosomes contribute disproportionately to reproductive isolation. However, in birds, which show a Z/W sex determination system, the role of adaptation versus genetic drift as the driving force of the faster differentiation of the Z chromosome (fast‐Z effect) and the disproportionate role of the Z chromosome in reproductive isolation (large‐Z effect) are still debated. Here, we address this debate in the bird genus Ficedula flycatchers based on population‐level whole‐genome sequencing data of six species. Our analysis provides evidence for both faster lineage sorting and reduced gene flow on the Z chromosome than the autosomes. However, these patterns appear to be driven primarily by the increased role of genetic drift on the Z chromosome, rather than an increased rate of adaptive evolution. Genomic scans of selective sweeps and fixed differences in fact suggest a reduced action of positive selection on the Z chromosome. [ABSTRACT FROM AUTHOR]

Aim: Evaluating the similarity of diversity patterns across micro‐ to macroevolutionary scales in natural communities, such as species–genetic diversity correlations (SGDCs), may inform on processes shaping community assembly. However, whether SGDCs not only hold across communities but also across lineages has never been explored so far. Here we investigated SGDCs across co‐distributed taxa for different spatial components (α, β, γ), and formally tested the influence of dispersal traits on β‐SGDCs. Location: Western Indian Ocean. Time period: 2016–2017. Major taxa studied: Tropical reef fish species with contrasting dispersal traits. Methods: Using double‐digest restriction‐site associated DNA sequencing (ddRADseq) Single Nucleotide Polymorphism data for 20 tropical reef fishes and distribution data of 2,446 species belonging to 12 families, we analysed the correlations between within‐species genetic diversity and within‐family species diversity (i.e., lineage diversity) for the three spatial components (α, β, γ‐SGDCs). We then related the strength of β‐SGDCs per species to proxies of larval dispersal abilities. Results: We detected positive and significant lineage‐based SGDC only for the β component, that is, the families showing the greatest level of species turnover among sites contain the species with the greatest levels of genetic differentiation. We showed that the Monsoon Drift mainly explained the β‐diversity patterns at both intraspecific and interspecific levels. Higher β‐SGDCs were found for species with short pelagic larval duration and weak larval swimming capacity. Main conclusions: Our study reveals a strong correlation between genetic and species β‐diversity, a result explained by the presence of a 'soft' barrier and mediated by larval dispersal processes. This suggests that vicariance and dispersal limitation are major processes shaping β‐diversity patterns from microevolutionary to macroevolutionary scales in tropical reef fishes. [ABSTRACT FROM AUTHOR]

Hybridization is an evolutionary process with wide‐ranging potential outcomes, from providing populations with important genetic variation for adaptation to being a substantial fitness cost leading to extinction. Here, we focussed on putative hybridization between two morphologically distinct species of New Zealand grasshopper. We collected Phaulacridium marginale and Phaulacridium otagoense specimens from a region where mitochondrial introgression had been detected and where their habitat has been modified by introduced mammals eating the natural vegetation and by the colonization of many non‐native plant species. In contrast to observations in the 1970s, our sampling of wild pairs of grasshoppers in copula provided no evidence of assortative mating with respect to species. Geometric morphometrics on pronotum shape of individuals from areas of sympatry detected phenotypically intermediate specimens (putative hybrids), and the distribution of phenotypes in most areas of sympatry was found to be unimodal. These results suggest that hybridization associated with anthropogenic habitat changes has led to these closely related species forming a hybrid swarm, with random mating. Without evidence of hybrid disadvantage, we suggest a novel hybrid lineage might eventually result from the merging of these two species. [ABSTRACT FROM AUTHOR]

Back-to-back GCPW-MS-GCPW (Grounded Coplanar Waveguide-Microstrip lines) transitions realized on benzocyclobutene polymer thin films (20 μm) and using copper metallization are presented in this article. The achieved experimental bandwidth is 82 GHz with a remarkably lower cutoff frequency of only 1.5 GHz and insertion loss of 0.5 dB. This performance is obtained without neither making via holes in the substrate nor patterning the bottom ground plane. These transitions make easier and faster manufacturing and characterization, by means of coplanar probes, of microwave devices realized from materials in thin film and whose driving electrode is a MS line. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:2041-2045, 2015 [ABSTRACT FROM AUTHOR]

Slow-wave coplanar striplines (S-CPS) have been implemented in the standard AMS 0.35 μm CMOS technology. Compared to conventional coplanar striplines (CPS), at 20 GHz, the proposed S-CPS line has more than 675% increase in quality factor, 54% improvement in the attenuation constant and 72% reduction in the electrical length. The RLCG model has also been extracted and the sources of losses have been identified. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:650-654, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26645 [ABSTRACT FROM AUTHOR]

This article presents an improved factor of merit for the comparison of center-frequency tunable bandpass filters. This study draws up a comparison between existing tunable filters for which different commonly used parameters demonstrating their performance are given. A first factor of merit that takes all the major characteristics of such tunable filters into account is introduced. A second factor of merit is proposed to evaluate the filter compactness. These new factors of merit are applied for the comparison of more than 30 recently published papers. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 985–988, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24220 [ABSTRACT FROM AUTHOR]

In this article, shielded coplanar striplines (S-CPS) are studied to achieve slow-wave transmission lines in a CMOS process. The slow-wave propagation is achieved by placing floating strips below the CPS transmission line. The propagation parameters of such transmission lines are derived by simulations by means of a “full wave” 3D EM software. Quality factors as high as 35 at 10 GHz together with effective dielectric constants of 78 are reported. If these simulation results are confirmed by measurements, this would open the door to the possible realization of integrated transmission line-based RF circuits such as power dividers, phase-shifters, or filters of medium bandwidth below 10 GHz. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 352–358, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24054 [ABSTRACT FROM AUTHOR]

To be faster and more precise than the numerical technique for the computation of the photo-induced plasma in semiconductor, an analytical solution has to be developed. In this article, the Hankel transform is used to simplify the solution of the differential equation of second order with nonsconstant coefficient, known as the diffusion equations. The resulting expression of the 3D carrier density includes all the physical parameters of the substrate and the laser beam as well. A parametric study was also feasible using the developed expressions. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1718–1721, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21754 [ABSTRACT FROM AUTHOR]

This paper presents the first investigation of a novel method to obtain an apodization effect on common InP ridge waveguide filters. It consists of the use of particular sampled gratings. Such apodized filters measured transmission spectra present an enhanced rejection of about 20 dB of the adjacent sidelobes, which experimentally validate the concept. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1627–1630, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21682 [ABSTRACT FROM AUTHOR]

This paper presents an optically controlled broadband phase-shifter using a parallel-line coupler, that takes advantage of high-resistivity silicon photo-absorption at 840 nm. A continuously variable phase-shifting of 120° is achieved at 11 GHz with Δ|S21| < 5 dB and with |S11| < -15 dB in a large frequency band (6–15 GHz). © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 47: 570–573, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21232 [ABSTRACT FROM AUTHOR]

This paper deals with the 3D modeling of the photo-induced load created by a laser that illuminates a semiconductor substrate. This independent optical command allows us to change the microwave behavior of the microstrip device. We present a 3D-equivalent microwave model for the photo-injection in terms of equivalent conductivity plasma. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 356–359, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11380 [ABSTRACT FROM AUTHOR]

The optically controlled phase and magnitude of a coplanar transmitted wave have been investigated, taking advantage of the benefit of silicon photo-absorption at 843 nm. A phase-shift of 45° has been achieved at 12 GHz while the magnitude remains constant. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 129–132, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10993 [ABSTRACT FROM AUTHOR]

The photoinduced load obtained by illuminating the open end of a microstrip line on a semiconductor substrate is reported to be dependent on the nature of the metal/semiconductor contact. We have used the R//C model to study the photoinduced behavior according to the applied dc voltages, optical powers, and microwave signal frequency. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 257–261, 2001. [ABSTRACT FROM AUTHOR]

A metallic microstrip line deposited on silicon, illuminated at its end while its entry is being connected to an ultra-high-frequency generator, presents a photoinduced load at its extremity. By performing a mixing frequency experiment, it has been proved that this load actually behaves as a nonlinear element. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 29: 309–312, 2001. [ABSTRACT FROM AUTHOR]

We have shown that, if a microstrip line deposited on silicon is illuminated at its end, a nonlinear load is obtained which behaves in microwave like a “photoinduced varactor.” We have obtained this result experimentally, and by solving the Poisson's equation and the two carrier continuity equations. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 26: 10–13, 2000. [ABSTRACT FROM AUTHOR]

Using a 219 bipolar physical model a comparison is made between GaAs and AllnAs/GaInAs MSM PD performance (cutoff frequency and quantum efficiency) as a function of the device parameters. This covers the applied potential, electrode spacing, absorbing layer thickness, and heterojunction effect. We also reported that for millimeter-wave applications we can expect higher operating frequency using an AllnAs / GaInAs MSP PD, whereas we can expect higher quantum efficiency using a GaAs MSM PD. [ABSTRACT FROM AUTHOR]

Static and dynamic behaviors of multielectrode lasers are, for the first time, studied using an equivalent circuit model. The model is based on the monomode rate equations and the Fermi integral. The potential controlled absorption in the active-region quantum wells and its saturation are included as well as the different carrier recombination mechanisms. The model predicts a higher resonance amplitude and a -20-dB/decade slope above resonance instead of the commonly known -40-dB/decade slope for direct current modulation and consequently higher cutoff frequencies are to be expected for such structures. We also discuss briefly the impedance level of such structures as well as the different phenomena to be taken into account far a more precise representation. [ABSTRACT FROM AUTHOR]

We present theoretical and experimental results on an analog-fiber optic link using commercially available, or so, optoelectronic devices. The directly modulated experimental link operates at 850 MHz and an improvement of 11.5 dB on insertion loss has been obtained using passive reactive networks. The experimental optical link has shown an electrical insertion loss of -8 dB. The respective contributions of emitter and receiver modules have been clearly pointed out. [ABSTRACT FROM AUTHOR]

We present a new large/small signal equivalent circuit for semiconductor lasers, valid for above- as well as below-threshold operating conditions, based on the monomode rate equations and a polynomial approximation of Fermi integral. The model is thus valid for conditions of large injection. Results obtained by this model match perfectly those obtained by numerical integration of the rate equations. The equivalent circuit is easy to implement and solve on a nonlinear circuit analysis software such as SPICE and consequently allows the study of the parasitic effects as well as the laser behavior in complex circuits. Comparison between this model and previously published models is presented. The model is applied to the study of various heterojunction laser diodes, the experimental results of which have been published elsewhere. [ABSTRACT FROM AUTHOR]

We present the design and realization of a 1×4 switching matrix, based on an electro-optical directional coupler. This matrix is devoted to true time delay systems. It is characterized by an original topology that reduces global power consumption down to 20 mW. Fiber-to-fiber losses are 15 dB, and the crosstalk is lower than -20 dB. © 1998 John Wiley & Sons, Inc. Microwave Opt Technol Lett 18: 243–246, 1998. [ABSTRACT FROM AUTHOR]

A fiber radio link based on direct optical injection subharmonic locking of a GaAs MMIC oscillator at 10.6 GHz is experimentally demonstrated. Microwave output power of 7.6 dBm is reported. The oscillator can be locked using up to the 32nd subharmonic over a 200 kHz locking range. The achieved linewidth allowed transmission of a signal modulated down to 500 Hz through the link. © 1998 John Wiley & Sons, Inc. Microwave Opt Technol Lett 18: 193–196, 1998. [ABSTRACT FROM AUTHOR]

A three-terminal edge-coupled InGaAs/InP phototransistor is reported. A dc photocurrent gain near 60 and an optical unity gain frequency of 40 GHz were measured. The mixing of a modulated optical signal and a microwave signal applied on the base terminal is presented. Optical and electrical modeling are used to analyze and improve the device performances. © 1998 John Wiley & Sons, Inc. Microwave Opt Technol Lett 17: 408–412, 1998. [ABSTRACT FROM AUTHOR]

In this work we present a new optically controlled microwave matching technique. In this technique the gap between two microwave coupled lines is illuminated by an optical spot of suitable wavelength. The structure is then used as a load in a microwave circuit. By controlling the spot intensity and position, we control the matching frequency of the circuit. The microwave behavior of the illuminated load is obtained using the MMICAD (monolithic microwave integrated circuit analysis and design) simulator. Experimental results using a p-type Si substrate in agreement with the theoretical predictions are also obtained. [ABSTRACT FROM AUTHOR]

A small-signal equivalent circuit model of the multielectrode lasers with saturable absorbers based on a modified formulation of the rate equations is presented. The Auger recombinations are taken into consideration because they largely modify the carrier lifetime at the high carrier densities that occur in such structures. An analysis of the bistability of the power-current characteristic is presented. The model predicts an extremely high resonance amplitude as well as a very large bandwidth up to the millimetric range, which can be very interesting for microwave optical links. The results obtained using this model are comparable to those obtained using a large-signal equivalent circuit model implanted on SPICE, the results of which are published elsewhere. The equivalent circuit obtained is a tool suitable for the study of the behavior of the multielectrode laser within a microwave optical system. [ABSTRACT FROM AUTHOR]

Different simulation methods for analyzing microwave interconnects are presented. Dynamic and static as well as two-dimensional (2D) or three-dimensional (3D) methods are investigated, such as the method of moments (MoM) the SDM, and TLM method, in their specific domains of predilection. Results are finally compared together with those obtained from a commercial software product based can the FEM method. [ABSTRACT FROM AUTHOR]

A microwave integrated, tunable, low-pass filter is presented. This coplanar filter exhibits a wide tuning range of the cutoff frequency (±19% around 4.3 GHz) and a -30 dB stopband that extends up to 30 GHz. Insertion loss is 1.5 dB at low frequencies and return loss is better than 14 dB in the passband. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2566–2568, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23707 [ABSTRACT FROM AUTHOR]

The paper compares, in terms of the error vector magnitude (EVM), the transmission of two radiocellular standards (GSM and UMTS) on two different kinds of multimode fibre (glass optical fibre and polymer optical fibre). It has been so established that the perfluorinated graded index polymer optical fibre is able to carry on wireless signals through 300-m length using standard COTS components specifically designed for glass fibre. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1197–1199, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21582 [ABSTRACT FROM AUTHOR]

We report on the opto-microwave characterization of InP waveguide-coupled to microcavity disk resonators. The lateral waveguide confinement is obtained by deep inductively-coupled plasma reactive-ion etching (ICP-RIE) through the guiding layer. We demonstrate the propagation of microwaves on an optical carrier in this resonant structure, which behaves as an opto-microwave filter or demultiplexer. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 45: 315–317, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20808 [ABSTRACT FROM AUTHOR]

InGaAsP/InP micro-waveguides are fabricated by a deep (>3 μm) Reactive Ion Etching. The devices losses are measured by the Fabry–Perot technique for guide width contained between 10 μm and 0.5 μm. The measured losses range from 2 dB/mm to 14 dB/mm. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 216–218, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11333 [ABSTRACT FROM AUTHOR]

It is shown that local and large lattice mismatch epitaxies could be useful techniques for the fabrication of optoelectronic integrated circuits. As an example, we fabricated a monolithic resonant photoreceiver which associates a long-wavelength metal-semiconductor-metal photodetector, a GaAs MESFET preamplifier, and an inductor. The GaAs / GaInAs heteroepitaxy needed for the photodetector wax selectively grown using a SiO[sub2] mask and the entire circuit was fabricated on a silicon substrate. Compared to a PIN photodiode loaded with a 50-ω resistor, more than 10 dB gain was measured at 7 GHz in a microwave optical link. [ABSTRACT FROM AUTHOR]

We have measured the noise performance of GaInAs PIN photodiodes in the microwave frequency range. We show that the frequency response of the photodetector can be deduced from their photocurrent shot noise spectra. The noise level has been measured using a setup which is based on heterodyne microwave mixing. [ABSTRACT FROM AUTHOR]

An optically controlled coplanar waveguide gap on silicon has been investigated as a phase shifter. A large phase shift varying between 49 and 76° in the 1.4–12 GHz band is obtained under very low optical power (5 mW). © 1998 John Wiley & Sons, Inc. Microwave Opt Technol Lett 18: 56–58, 1998. [ABSTRACT FROM AUTHOR]

High-density low-loss dielectric optical interconnection is demonstrated on a monomode optical waveguide compatible with microelectronics technology. Low-loss self-aligned integrated mirrors (SAIM) on a dielectric (polyimide-silicon nitride-polyimide) optical waveguide have been fabricated. Optimization of the reactive ion etching process has been made in order to obtain vertical, homogeneous etched sidewalls. Using such a process, 45° integrated mirrors present reflection losses of 0.6 dB at a 830-nm wavelength (quasi-TE mode). [ABSTRACT FROM AUTHOR]

The purpose of this article is to compare the microwave performance of three photodetector types, an lnGaAs/lnP p-i-n photo-diode, an interdigitated lnA/As/ lnGaAs/ lnP metal-semiconductor-metal (MSM) photodiode, and an interdigitated lnGaAs/ lnP photo-conductor (PC). Static and dynamic characterizations have been carried out at 1.3.-µm wavelength using a directly modulated laser diode. Our experiments show that photoconductive detectors exhibit the best sensitivity for frequencies up to 3 GHz. [ABSTRACT FROM AUTHOR]

We describe an optically controlled microwave attenuator based on a microstrip reverse directional coupler where optical illumination modifies the loads at the coupling and transmission ports. A tunable attenuation up to 10 dB was measured at the center frequency, Experimental and theoretical results are compared and agree well. [ABSTRACT FROM AUTHOR]