Search results for "Extinction"

All-optical extinction-ratio enhancement of a 160 GHz pulse train by a saturable-absorber vertical microcavity

2006

International audience; A vertical-access passive all-optical gate has been used to improve the extinction ratio of a 160 GHz pico-second pulse train at 1555 nm. An extinction ratio enhancement of 6 dB is observed within an 8 nm bandwidth. Such a device is a promising candidate for low-cost all optical reamplication and reshaping (211) regeneration at 160 Gbits/s.

Dielectric-loaded plasmonic waveguide-ring resonators

2009

International audience; Using near-field microscopy, the performance of dielectric-loaded plasmonic waveguide-ring resonators (WRRs) operating at telecom wavelengths is investigated for various waveguide-ring separations. It is demonstrated that compact ( footprint similar to 150 mu m(2)) and efficient ( extinction ratio similar to 13 dB) WRR-based filters can be realized using UV-lithography. The WRR wavelength responses measured and calculated using the effective-index method are found in good agreement. (c) 2009 Optical Society of America

Cascadability and efficiency of a saturable absorber device inserted into a SMF transmission line for future 160-Gbit/s all-optical reshaping applica…

2007

In this prospective work, we analyze the cascadability and reshaping properties of a quantum well microcavity saturable absorber (SA) device cascaded inside a RZ-signal SMF-based transmission line to annihilate the ghost-pulse phenomenon taking place in the "...01010101..." 160-Gbit/s 2-bit pattern.

All-fibered high-quality 28-GHz to 112 GHz pulse sources based on nonlinear compression of optical temporal besselons

2021

The generation of high quality pulse trains at repetition rates of several tens of GHz remains a crucial step for optical telecommunications, optical sampling or component testing applications. Unfortunately, the current bandwidth limitations of optoelectronic devices do not allow the direct generation of well-defined optical pulse trains with low duty cycles. An attractive solution is based on a direct temporal phase modulation that is then converted into an intensity modulation thanks to a dispersive element that imprints a spectral quadratic phase. Picosecond pulses at repetition rates of several tens of GHz have been successfully demonstrated [1] . However, this approach suffers from a …

High-quality 10 and 20 GHz repetition rate optical sources based on the spectral phase tailoring of a temporal sinusoidal phase modulation

2019

International audience; We theoretically introduce and experimentally demonstrate a new approach to generate high-quality, high repetition-rate pulse trains. This method is based on a temporal sinusoidal phase modulation combined with a triangular spectral phase shaping. Experimental results validate the concept at repetition rates of 10 and 20 GHz.

Does landscape diversity influence species fitness in farmland plants ?

2015

In agriculture, landscape management research has proven extremely valuable for explaining species amount, such as how species capture and utilize changed landscape resources to maintain population size and community diversity. What is surprising is the apparent lack of comparable studies on the effects of landscape properties and management on species fitness. Here, we search for "pathological" situations where landscape effects on farmland plant amount mask significantly different effects on fitness. We examined the case of 83 weed species in 256 fields distributed across the UK national scale. Whether at the local scale of the neighborhood or the larger scale of 2 km, we find landscape e…

A paleontological viewpoint on the "6th mass exinction".

2020

Decreasing Phanerozoic extinction intensity as a consequence of Earth surface oxygenation and metazoan ecophysiology

2021

The decline in background extinction rates of marine animals through geologic time is an established but unexplained feature of the Phanerozoic fossil record. There is also growing consensus that the ocean and atmosphere did not become oxygenated to near-modern levels until the mid-Paleozoic, coinciding with the onset of generally lower extinction rates. Physiological theory provides us with a possible causal link between these two observations-predicting that the synergistic impacts of oxygen and temperature on aerobic respiration would have made marine animals more vulnerable to ocean warming events during periods of limited surface oxygenation. Here, we evaluate the hypothesis that chang…

Early Triassic proliferation of microbial deposit

2019

International audience; In modern examples of well-developed microbial-dominated deposits associated with metazoan organisms can be currently found in various environments including but not restricted to lagoons in Polynesia (Sprachta et al., 2001), the warm water of the Cuba (e.g., Bouton et al., 2016; Pace et al., 2018), the hypersaline lakes of the Great Salt Lake (USA; e.g., Bouton et al., 2016; Vennin et al., 2019; Vanden Berg, 2019), or the alkaline Satonda Crater Lake in Indonesia (Arp et al., 2003; Satuyana et al., 2010). In Early Triassic, several authors indicated that microbial deposits are frequently associated with sponges, bivalves, brachiopods, ostracods and echinoderms and d…

Clause compromissoire. Expiration du délai de l'arbitrage. Extinction de l'instance. Obligation de constituer un nouveau tribunal arbitral. Incompéte…

1999

International audience; (Cass. 2e civ., 18 févr. 1999, inédit, Igla c/ Sté Soulier et autres)