| 1. |
- Kattge, Jens, et al.
(författare)
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TRY plant trait database - enhanced coverage and open access
- 2020
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Ingår i: Global Change Biology. - : Wiley-Blackwell. - 1354-1013 .- 1365-2486. ; 26:1, s. 119-188
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Tidskriftsartikel (refereegranskat)abstract
- Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives.
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| 2. |
- Bogaerts, Wim, et al.
(författare)
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MORPHIC : Programmable Photonic Circuits enabled by Silicon Photonic MEMS
- 2020
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Ingår i: Proceedings Volume 11285 SPIE OPTO - 1-6 February 2020 Silicon Photonics XV. - : SPIE-Intl Soc Optical Eng.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In the European project MORPHIC we develop a platform for programmable silicon photonic circuits enabled by waveguide-integrated micro-electro-mechanical systems (MEMS). MEMS can add compact, and low-power phase shifters and couplers to an established silicon photonics platform with high-speed modulators and detectors. This MEMS technology is used for a new class of programmable photonic circuits, that can be reconfigured using electronics and software, consisting of large interconnected meshes of phase shifters and couplers. MORPHIC is also developing the packaging and driver electronics interfacing schemes for such large circuits, creating a supply chain for rapid prototyping new photonic chip concepts. These will be demonstrated in different applications, such as switching, beamforming and microwave photonics.
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| 3. |
- Quack, Niels, et al.
(författare)
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Integrated silicon photonic MEMS
- 2023
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Ingår i: MICROSYSTEMS & NANOENGINEERING. - : Springer Nature. - 2055-7434. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- Silicon photonics has emerged as a mature technology that is expected to play a key role in critical emerging applications, including very high data rate optical communications, distance sensing for autonomous vehicles, photonic-accelerated computing, and quantum information processing. The success of silicon photonics has been enabled by the unique combination of performance, high yield, and high-volume capacity that can only be achieved by standardizing manufacturing technology. Today, standardized silicon photonics technology platforms implemented by foundries provide access to optimized library components, including low-loss optical routing, fast modulation, continuous tuning, high-speed germanium photodiodes, and high-efficiency optical and electrical interfaces. However, silicon's relatively weak electro-optic effects result in modulators with a significant footprint and thermo-optic tuning devices that require high power consumption, which are substantial impediments for very large-scale integration in silicon photonics. Microelectromechanical systems (MEMS) technology can enhance silicon photonics with building blocks that are compact, low-loss, broadband, fast and require very low power consumption. Here, we introduce a silicon photonic MEMS platform consisting of high-performance nano-opto-electromechanical devices fully integrated alongside standard silicon photonics foundry components, with wafer-level sealing for long-term reliability, flip-chip bonding to redistribution interposers, and fibre-array attachment for high port count optical and electrical interfacing. Our experimental demonstration of fundamental silicon photonic MEMS circuit elements, including power couplers, phase shifters and wavelength-division multiplexing devices using standardized technology lifts previous impediments to enable scaling to very large photonic integrated circuits for applications in telecommunications, neuromorphic computing, sensing, programmable photonics, and quantum computing.
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| 4. |
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| 5. |
- Bogaerts, Wim, et al.
(författare)
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Programmable Photonic Circuits powered by Silicon Photonic MEMS Technology
- 2022
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Ingår i: Photonic Networks and Devices, Networks 2022. - : Optica Publishing Group (formerly OSA).
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Konferensbidrag (refereegranskat)abstract
- Programmable photonic chips allow flexible reconfiguration of on-chip optical connections, controlled through electronics and software. We will present the recent progress of such complex photonic circuits powered by silicon photonic MEMS actuators.
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| 6. |
- Bogaerts, Wim, et al.
(författare)
-
Programmable silicon photonic circuits powered by MEMS
- 2022
-
Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE-Intl Soc Optical Eng.
-
Konferensbidrag (refereegranskat)abstract
- We present our work to extend silicon photonics with MEMS actuators to enable low-power, large scale programmable photonic circuits. For this, we start from the existing iSiPP50G silicon photonics platform of IMEC, where we add free-standing movable waveguides using a few post-processing steps. This allows us to implement phase shifters and tunable couplers using electrostatically actuated MEMS, while at the same time maintaining all the original functionality of the silicon photonics platform. The MEMS devices are protected using a wafer-level sealing approach and interfaced with custom multi-channel driver and readout electronics.
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| 7. |
- Bogaerts, Wim, et al.
(författare)
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Scaling programmable silicon photonics circuits
- 2023
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Ingår i: Silicon Photonics XVIII. - : SPIE-Intl Soc Optical Eng.
-
Konferensbidrag (refereegranskat)abstract
- We give an overview the progress of our work in silicon photonic programmable circuits, covering the techn stack from the photonic chip over the driver electronics, packaging technologies all the way to the sof layers. On the photonic side, we show our recent results in large-scale silicon photonic circuits with diff tuning technologies, including heaters, MEMS and liquid crystals, and their respective electronic driving sch We look into the scaling potential of these different technologies as the number of tunable elements in a ci increases. Finally, we elaborate on the software routines for routing and filter synthesis to enable the pho programmer.
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| 8. |
- De Frenne, Pieter, et al.
(författare)
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Microclimate moderates plant responses to macroclimate warming
- 2013
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 110:46, s. 18561-18565
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Tidskriftsartikel (refereegranskat)abstract
- Recent global warming is acting across marine, freshwater, and terrestrial ecosystems to favor species adapted to warmer conditions and/or reduce the abundance of cold-adapted organisms (i.e., thermophilization of communities). Lack of community responses to increased temperature, however, has also been reported for several taxa and regions, suggesting that climatic lags may be frequent. Here we show that microclimatic effects brought about by forest canopy closure can buffer biotic responses to macroclimate warming, thus explaining an apparent climatic lag. Using data from 1,409 vegetation plots in European and North American temperate forests, each surveyed at least twice over an interval of 12-67 y, we document significant thermophilization of ground-layer plant communities. These changes reflect concurrent declines in species adapted to cooler conditions and increases in species adapted to warmer conditions. However, thermophilization, particularly the increase of warm-adapted species, is attenuated in forests whose canopies have become denser, probably reflecting cooler growing-season ground temperatures via increased shading. As standing stocks of trees have increased in many temperate forests in recent decades, local microclimatic effects may commonly be moderating the impacts of macroclimate warming on forest understories. Conversely, increases in harvesting woody biomass-e.g., for bioenergy-may open forest canopies and accelerate thermophilization of temperate forest biodiversity.
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| 9. |
- De Schuyter, Wim, et al.
(författare)
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Declining potential nectar production of the herb layer in temperate forests under global change
- 2024
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Ingår i: Journal of Ecology. - 0022-0477 .- 1365-2745. ; 112:4, s. 832-847
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Tidskriftsartikel (refereegranskat)abstract
- Wild pollinators are crucial for ecosystem functioning and human food production and often rely on floral resources provided by different (semi-) natural ecosystems for survival. Yet, the role of European forests, and especially the European forest herb layer, as a potential provider of floral resources for pollinators has scarcely been quantified.In this study, we measured the potential nectar production (PNP) of the forest herb layer using resurvey data across 3326 plots in temperate forests in Europe, with an average time interval of 41 years between both surveys in order to assess (i) the importance of the forest herb layer in providing nectar for wild pollinators, (ii) the intra-annual variation of PNP, (iii) the overall change in PNP between survey periods and (iv) the change in intra-annual variation of PNP between survey periods. The PNP estimates nectar availability based on the relative cover of different plant species in the forest herb layer. Although PNP overestimates actual nectar production, relative differences amongst plots provide a valid and informative way to analyse differences across time and space.Our results show that the forest herb layer has a large potential for providing nectar for wild pollinator communities, which is greatest in spring, with an average PNP of almost 16 g sugar/m2/year. However, this potential has drastically declined (mean plot-level decline >24%).Change in light availability, associated with shifts in canopy structure and canopy composition, is the key driver of temporal PNP changes.Synthesis. Our study shows that if management activities are carefully planned to sustain nectar-producing plant species for wild pollinators, European forest herb layers and European forests as a whole can play key roles in sustaining wild pollinator populations.
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| 10. |
- Douven, Igor, et al.
(författare)
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Similarity-based reasoning in conceptual spaces
- 2023
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Ingår i: Frontiers in Psychology. - 1664-1078. ; 14
-
Tidskriftsartikel (refereegranskat)abstract
- Whereas the validity of deductive inferences can be characterized in terms of their logical form, this is not true for all inferences that appear pre-theoretically valid. Nonetheless, philosophers have argued that at least some of those inferences—sometimes called “similarity-based inferences” —can be given a formal treatment with the help of similarity spaces, which are mathematical spaces purporting to represent human similarity judgments. In these inferences, we conclude that a given property pertains to a category of items on the grounds that the same property pertains to a similar category of items. We look at a specific proposal according to which the strength of such inferences is a function of the distance, as measured in the appropriate similarity space, between the category referenced in the premise and the category referenced in the conclusion. We report the outcomes of three studies that all support the said proposal.
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| 11. |
- Edinger, Pierre, et al.
(författare)
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A Bistable Silicon Photonic Mems Phase Switch For Nonvolatile Photonic Circuits
- 2022
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Konferensbidrag (refereegranskat)abstract
- Silicon photonic circuits are rapidly growing in complexity and spreading to new applications. However, programmable circuits consume much power and require active electrical interfaces. For the first time, we demonstrate a nonvolatile photonic MEMS π-phase switch using dual comb-drive actuation and adhesion forces, implemented in a silicon photonics foundry. Both nonvolatile states are low-loss, display low dispersion, could be cycled through over 100 times, and have retention times over 12 hours. We believe that the demonstrated nonvolatility combined with excellent optical performance can enable a new generation of programmable photonic chips that do not consume any electrical power once (re)configured.
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| 12. |
- Edinger, Pierre, et al.
(författare)
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A MEMS tunable phase monitor with integrated photodiode read-out for silicon photonic circuits
- 2023
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Ingår i: Integrated Photonics Research, Silicon and Nanophotonics in Proceedings Advanced Photonics Congress 2023 - Part of Advanced Photonics Congress 2023. - : Optica Publishing Group.
-
Konferensbidrag (refereegranskat)abstract
- Electrostatic MEMS provide low power consumption to programmable photonics. However, the scaling of programmable photonics also requires solutions for circuit monitoring. We demonstrate a MEMS tunable phase monitor with integrated read-out on a foundry platform.
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| 13. |
- Edinger, Pierre, et al.
(författare)
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A vacuum-sealed silicon photonic MEMS tunable ring resonator with independent control over coupling and phase
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Ring resonators are a vital element for designing filters, optical delay lines, or sensors in silicon photonics. However, reconfigurable ring resonators with low-power consumption and good optical performance are not available in foundries today. We demonstrate an add-drop ring resonator with the independent tuning of coupling and round-trip phase using low-power microelectromechanical (MEMS) actuation. The MEMS rings are individually vacuum-sealed on wafer scale, enabling reliable long-term operation with low damping. On resonance, we demonstrate a modulation increase of up to 15 dB, with a voltage bias of 4V and a peak drive amplitude as low as 20mV.
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| 14. |
- Edinger, Pierre, et al.
(författare)
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Add-drop silicon ring resonator with low-power MEMS tuning of phase and coupling
- 2022
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Ingår i: 2022 Conference on Lasers and Electro-Optics, CLEO 2022. - : Institute of Electrical and Electronics Engineers Inc..
-
Konferensbidrag (refereegranskat)abstract
- Applications of silicon photonics range from sensing to microwave processing. However, low-power active filters with long FSRs are lacking. We demonstrate an add-drop ring filter with 4 nm FSR and nW-level MEMS tuning of phase and coupling.
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| 15. |
- Edinger, Pierre, et al.
(författare)
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An Integrated Platform for Cavity Optomechanics with Vacuum-Sealed Silicon Photonic MEMS
- 2023
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Ingår i: 2023 22nd International Conference on Solid-State Sensors, Actuators and Microsystems, Transducers 2023. - : Institute of Electrical and Electronics Engineers Inc.. ; , s. 425-428
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Konferensbidrag (refereegranskat)abstract
- Silicon photonics is an excellent platform for integrated cavity optomechanics due to silicon's high light confinement and favorable mechanical properties. However, optomechanical devices require a vacuum environment to inhibit damping due to air.We present an integrated platform for cavity optomechanics using thermo-compression bonding of silicon caps to provide on-chip vacuum sealing. We demonstrate optomechanical coupling in a vacuum-sealed ring resonator implemented on the platform, either by modulation of the laser power or by using an electrostatic phase shifter in the ring.By enabling optomechanics on a standard platform, we aim to make the technology available to a wider user base.
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| 16. |
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| 17. |
- Edinger, Pierre, et al.
(författare)
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Silicon photonic microelectromechanical phase shifters for scalable programmable photonics
- 2021
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Ingår i: Optics Letters. - : OSA. - 0146-9592 .- 1539-4794. ; 46:22, s. 5671-5674
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Tidskriftsartikel (refereegranskat)abstract
- Programmable photonic integrated circuits are emerging as an attractive platform for applications such as quantum information processing and artificial neural networks. However, current programmable circuits are limited in scalability by the lack of low-power and low-loss phase shifters in commercial foundries. Here, we demonstrate a compact phase shifter with low-power photonic microelectromechanical system (MEMS) actuation on a silicon photonics foundry platform (IMEC’s iSiPP50G). The device attains (2.9π±π) phase shift at 1550 nm, with an insertion loss of (0.33\textminus0.10$+$0.15)dB, a Vπ of (10.7\textminus1.4$+$2.2)V, and an Lπ of (17.2\textminus4.3$+$8.8)µm. We also measured an actuation bandwidth f\textminus3dB of 1.03 MHz in air. We believe that our demonstration of a low-loss and low-power photonic MEMS phase shifter implemented in silicon photonics foundry compatible technology lifts a main roadblock toward the scale-up of programmable photonic integrated circuits.
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| 18. |
- Edinger, Pierre, et al.
(författare)
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Vacuum-sealed silicon photonic MEMS tunable ring resonator with an independent control over coupling and phase
- 2023
-
Ingår i: Optics Express. - : Optica Publishing Group. - 1094-4087. ; 31:4, s. 6540-6551
-
Tidskriftsartikel (refereegranskat)abstract
- Ring resonators are a vital element for filters, optical delay lines, or sensors in silicon photonics. However, reconfigurable ring resonators with low-power consumption are not available in foundries today. We demonstrate an add-drop ring resonator with the independent tuning of round-trip phase and coupling using low-power microelectromechanical (MEMS) actuation. At a wavelength of 1540 nm and for a maximum voltage of 40 V, the phase shifters provide a resonance wavelength tuning of 0.15 nm, while the tunable couplers can tune the optical resonance extinction ratio at the through port from 0 to 30 dB. The optical resonance displays a passive quality factor of 29 000, which can be increased to almost 50 000 with actuation. The MEMS rings are individually vacuum-sealed on wafer scale, enabling reliable and long-term protection from the environment. We cycled the mechanical actuators for more than 4 x 109 cycles at 100 kHz, and did not observe degradation in their response curves. On mechanical resonance, we demonstrate a modulation increase of up to 15 dB, with a voltage bias of 4 V and a peak drive amplitude as low as 20 mV.
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| 19. |
- Eeraerts, Maxime, et al.
(författare)
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Pollination deficits and their relation with insect pollinator visitation are cultivar-dependent in an entomophilous crop
- 2024
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Ingår i: Agriculture, Ecosystems and Environment. - 0167-8809. ; 369
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Tidskriftsartikel (refereegranskat)abstract
- Insects contribute considerably to global crop pollination, with pollination deficits being documented for multiple entomophilous or pollinator-dependent crops. Different cultivars of crops are being cultivated within and across production regions, so it is essential to understand the cultivar variability of pollination deficits. Here, we used a dataset from 286 sites from multiple production regions to develop a synthesis on pollination deficits in two widely cultivated highbush blueberry cultivars, ‘Bluecrop’ and ‘Duke’. Additionally, we determined if bee visitation or bee richness reduces pollination deficits in these cultivars. On average, neither cultivar showed pollination deficits regarding fruit set. However, for ‘Bluecrop’ we found pollination deficits for berry weight and seed set, which was not the case for ‘Duke’. Increasing total bee visitation reduced pollination deficits of both berry weight and seed set for ‘Bluecrop’. More specifically, a non-linear, negative exponential model best predicted this relation between bee visitation and pollination deficits. Our results highlight that pollination deficits and responses to pollinator visitation are variable between different cultivars of a single crop, which suggests opportunities to use certain cultivars that are less dependent on insect-mediated pollination in landscapes and regions where pollination services have been compromised. In addition, the non-linear response between bee visitation and pollination deficits suggests that optimal bee visitation rates need to be determined to improve pollination management and crop yield and to support accurate economic valuations of pollination services.
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| 20. |
- Jo, Gaehun, 1992-, et al.
(författare)
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Wafer-level Hermetic Sealing of Silicon Photonic MEMS by Direct Metal-to-Metal Bonding
- 2022
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The field of silicon (Si) photonic micro-electromechanical system (MEMS) for photonic integrated circuits (PICs) has evolved rapidly. Thanks to the ultra-low power consumption of Si photonic MEMS, it enables a wide range of high-performance photonic devices such as integrated optical MEMS phase shifters, tunable couplers and switches. However, photonic MEMS have suspended and movable parts which need to be protected from environmental influences, such as exposure to dust and humidity. Therefore, a packaging solution is needed for reliable operation over long periods. Here, we demonstrate wafer-level vacuum sealing of Si photonic MEMS inside cavities with ultra-thin Si caps.
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| 21. |
- Jo, Gaehun, 1992-, et al.
(författare)
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Wafer-level hermetically sealed silicon photonic MEMS
- 2022
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Ingår i: Photonics Research. - : Optical Society of America. - 2327-9125. ; 10:2, s. A14-A21
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Tidskriftsartikel (refereegranskat)abstract
- The emerging fields of silicon (Si) photonic micro–electromechanical systems (MEMS) and optomechanics enable a wide range of novel high-performance photonic devices with ultra-low power consumption, such as integrated optical MEMS phase shifters, tunable couplers, switches, and optomechanical resonators. In contrast to conventional SiO2-clad Si photonics, photonic MEMS and optomechanics have suspended and movable parts that need to be protected from environmental influence and contamination during operation. Wafer-level hermetic sealing can be a cost-efficient solution, but Si photonic MEMS that are hermetically sealed inside cavities with optical and electrical feedthroughs have not been demonstrated to date, to our knowledge. Here, we demonstrate wafer-level vacuum sealing of Si photonic MEMS inside cavities with ultra-thin caps featuring optical and electrical feedthroughs that connect the photonic MEMS on the inside to optical grating couplers and electrical bond pads on the outside. We used Si photonic MEMS devices built on foundry wafers from the iSiPP50G Si photonics platform of IMEC, Belgium. Vacuum confinement inside the sealed cavities was confirmed by an observed increase of the cutoff frequency of the electro-mechanical response of the encapsulated photonic MEMS phase shifters, due to reduction of air damping. The sealing caps are extremely thin, have a small footprint, and are compatible with subsequent flip-chip bonding onto interposers or printed circuit boards. Thus, our approach for sealing of integrated Si photonic MEMS clears a significant hurdle for their application in high-performance Si photonic circuits.
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| 22. |
- Jo, Gaehun, 1992-, et al.
(författare)
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Wafer-Level Vacuum Sealing for Packaging of Silicon Photonic MEMS
- 2021
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Ingår i: Proceedings SPIE OPTO 6-12 march 2021 silicon photonics XVI. - : SPIE-Intl Soc Optical Eng.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Silicon (Si) photonic micro-electro-mechanical systems (MEMS), with its low-power phase shifters and tunable couplers, is emerging as a promising technology for large-scale reconfigurable photonics with potential applications for example in photonic accelerators for artificial intelligence (AI) workloads. For silicon photonic MEMS devices, hermetic/vacuum packaging is crucial to the performance and longevity, and to protect the photonic devices from contamination. Here, we demonstrate a wafer-level vacuum packaging approach to hermetically seal Si photonic MEMS wafers produced in the iSiPP50G Si photonics foundry platform of IMEC. The packaging approach consists of transfer bonding and sealing the silicon photonic MEMS devices with 30 µm-thick Si caps, which were prefabricated on a 100 mm-diameter silicon-on-insulator (SOI) wafer. The packaging process achieved successful wafer-scale vacuum sealing of various photonic devices. The functionality of photonic MEMS after the hermetic/vacuum packaging was confirmed. Thus, the demonstrated thin Si cap packaging shows the possibility of a novel vacuum sealing method for MEMS integrated in standard Si photonics platforms.
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| 23. |
- Khan, Umar, et al.
(författare)
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Low power actuators for programmable photonic processors
- 2023
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Ingår i: AI and Optical Data Sciences IV. - : SPIE-Intl Soc Optical Eng.
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Konferensbidrag (refereegranskat)abstract
- The demand for efficient actuators in photonics has peaked with increasing popularity for large-scale general-purpose programmable photonics circuits. We present our work to enhance an established silicon photonics platform with low-power micro-electromechanical (MEMS) and liquid crystal (LC) actuators to enable large-scale programmable photonic integrated circuits (PICs).
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| 24. |
- Khan, Umar, et al.
(författare)
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MORPHIC : MEMS enhanced silicon photonics for programmable photonics
- 2022
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Ingår i: Integrated Photonics Platforms Ii. - : SPIE-Intl Soc Optical Eng.
-
Konferensbidrag (refereegranskat)abstract
- We present our work in the European project MORPHIC to extend an established silicon photonics platform with low-power and non-volatile micro-electromechanical (MEMS) actuators to demonstrate large-scale programmable photonic integrated circuits (PICs).
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| 25. |
- Li, Yingying, 1994-, et al.
(författare)
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Design and fabrication of a 4-terminal in-plane nanoelectromechanical relay
- 2023
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Konferensbidrag (refereegranskat)abstract
- We present 4-terminal (4-T) silicon (Si) nanoelectronmechanical (NEM) relays fabricated on silicon-oninsulator (SOI) wafers. We demonstrate true 4-T switching behavior with isolated control and signal paths. A pull-in voltage as low as 11.6 V is achieved with the miniaturized design. 4-T NEM relays are a very promising candidate for building ultra-low-power logic circuits since they enable novel circuit architectures to realize logic functions with far fewer devices than CMOS implementations, while also allowing the dynamic power consumption to be reduced by body-biasing.
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| 26. |
- Li, Yingying, 1994-, et al.
(författare)
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Integrated 4-terminal single-contact nanoelectromechanical relays implemented in a silicon-on-insulator foundry process
- 2023
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Ingår i: Nanoscale. - : Royal Society of Chemistry. - 2040-3364 .- 2040-3372.
-
Tidskriftsartikel (refereegranskat)abstract
- Integrated nanoelectromechanical (NEM) relays can be used instead of transistors to implement ultra-low power logic circuits, due to their abrupt turn-off characteristics and zero off-state leakage. Further, realizing circuits with 4-terminal (4-T) NEM relays enables significant reduction in circuit device count compared to conventional transistor circuits. For practical 4-T NEM circuits, however, the relays need to be miniaturized and integrated with high-density back-end-of-line (BEOL) interconnects, which is challenging and has not been realized to date. Here, we present electrostatically actuated silicon 4-T NEM relays that are integrated with multi-layer BEOL metal interconnects, implemented using a commercial silicon-on-insulator (SOI) foundry process. We demonstrate 4-T switching and the use of body-biasing to reduce pull-in voltage of a relay with a 300 nm airgap, from 15.8 V to 7.8 V, consistent with predictions of the finite-element model. Our 4-T NEM relay technology enables new possibilities for realizing NEM-based circuits for applications demanding harsh environment computation and zero standby power, in industries such as automotive, Internet-of-Things, and aerospace.
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| 27. |
- Quack, Niels, et al.
(författare)
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MEMS-Enabled Silicon Photonic Integrated Devices and Circuits
- 2020
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Ingår i: IEEE Journal of Quantum Electronics. - : IEEE. - 0018-9197 .- 1558-1713. ; 56:1
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Tidskriftsartikel (refereegranskat)abstract
- Photonic integrated circuits have seen a dramatic increase in complexity over the past decades. This development has been spurred by recent applications in datacenter communications and enabled by the availability of standardized mature technology platforms. Mechanical movement of wave-guiding structures at the micro- and nanoscale provides unique opportunities to further enhance functionality and to reduce power consumption in photonic integrated circuits. We here demonstrate integration of MEMS-enabled components in a simplified silicon photonics process based on IMEC's Standard iSiPP50G Silicon Photonics Platform and a custom release process.
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| 28. |
- Quack, N., et al.
(författare)
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Scalable Nano-Opto-Electromechanical Systems in Silicon Photonics
- 2021
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Ingår i: 2021 IEEE Photonics Conference, IPC 2021 - Proceedings. - : Institute of Electrical and Electronics Engineers (IEEE).
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Konferensbidrag (refereegranskat)abstract
- Recent advances in integration of Nano-Opto-Electromechanical Systems in Silicon Photonics enable fundamental photonic operations such as switching, phase shifting or power equalization on-chip. The unique combination of high optical efficiency, low electric power consumption and compact footprint, provides outstanding opportunities in scalability to large-scale photonic integrated circuits.
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| 29. |
- Rajendran, Khannan, et al.
(författare)
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Thermo-mechanical Noise Measurement of Sealed Nanobeams on a Silicon Photonics-MEMS Platform
- 2021
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Ingår i: 2021 IEEE 17Th International Conference On Group Iv Photonics (GFP 2021). - : Institute of Electrical and Electronics Engineers (IEEE).
-
Konferensbidrag (refereegranskat)abstract
- The thermal motion of a vacuum packaged, suspended nano-beam and nanophotonic waveguide on a silicon photonics-MEMS platform is measured. The resonance frequency and Q-factor of the observed mechanical modes are determined. We also experimentally estimate the displacement sensitivity to be 1.779 +/- 0.022 fm/root Hz.
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| 30. |
- Sarneel, Judith M., et al.
(författare)
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Reading tea leaves worldwide : decoupled drivers of initial litter decomposition mass-loss rate and stabilization
- 2024
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Ingår i: Ecology Letters. - : John Wiley & Sons. - 1461-023X .- 1461-0248. ; 27:5
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Tidskriftsartikel (refereegranskat)abstract
- The breakdown of plant material fuels soil functioning and biodiversity. Currently, process understanding of global decomposition patterns and the drivers of such patterns are hampered by the lack of coherent large-scale datasets. We buried 36,000 individual litterbags (tea bags) worldwide and found an overall negative correlation between initial mass-loss rates and stabilization factors of plant-derived carbon, using the Tea Bag Index (TBI). The stabilization factor quantifies the degree to which easy-to-degrade components accumulate during early-stage decomposition (e.g. by environmental limitations). However, agriculture and an interaction between moisture and temperature led to a decoupling between initial mass-loss rates and stabilization, notably in colder locations. Using TBI improved mass-loss estimates of natural litter compared to models that ignored stabilization. Ignoring the transformation of dead plant material to more recalcitrant substances during early-stage decomposition, and the environmental control of this transformation, could overestimate carbon losses during early decomposition in carbon cycle models.
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| 31. |
- Sattari, Hamed, et al.
(författare)
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Low-voltage silicon photonic mems switch with vertical actuation
- 2021
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Ingår i: 2021 34th ieee international conference on micro electro mechanical systems (mems 2021). - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 298-301
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Konferensbidrag (refereegranskat)abstract
- We present a vertically movable silicon photonic MEMS switch realized in IMEC's standard silicon photonics platform followed by a dedicated postprocessing for MEMS release. The device has six optical ports, which enable four switching configurations with a safe electrical isolation of the switch's actuator. A low actuation voltage of 3.75 V is required to efficiently switch the optical signal from the drop port to the through port of the device. The device exhibits port extinctions of 16 dB and 26 dB at its OFF and ON states, respectively. With an insertion loss of < 2 dB and a broad 3 dB-bandwidth > 35 nm, this component paves the way for low-power scalable circuits in MEMS-enabled silicon photonics.
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| 32. |
- Sattari, Hamed, et al.
(författare)
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Silicon Photonic MEMS Add-Drop Filter
- 2021
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Ingår i: 2020 european conference on optical communications (ecoc). - : Institute of Electrical and Electronics Engineers (IEEE).
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Konferensbidrag (refereegranskat)abstract
- We demonstrate a compact add-drop filter based on a MEMS ring resonator implemented in IMEC's iSiPP50G silicon photonics platform. The device exhibits a port extinction of 20 dB and a port isolation of > 50 dB, upon actuation range of 0 V to 27 V.
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| 33. |
- Sattari, Hamed, et al.
(författare)
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Silicon photonic microelectromechanical systems add-drop ring resonator in a foundry process
- 2022
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Ingår i: JOURNAL OF OPTICAL MICROSYSTEMS. - : SPIE-Intl Soc Optical Eng. - 2708-5260. ; 2:04
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Tidskriftsartikel (refereegranskat)abstract
- Photonic add-drop filters are crucial components for the implementation of wavelength division multiplexing (WDM) in fiber-optic communication systems. The recent progress in photonic integration has shown the potential to integrate photonic add-drop filters alongside high-performance photonic building blocks on a chip to construct compact and complex photonic-integrated circuits for WDM. Typically, implementations are based on micro-ring resonators with integrated heaters or free carrier dispersion-based modulators to adjust the filter wavelength. However, heaters suffer from high power consumption, and free carriers result in optical absorption losses, limiting the scalability toward very-large-scale circuits. We demonstrate the design, simulation, fabrication, and experimental characterization of a compact add-drop filter based on a vertically movable, MEMS-actuated ring resonator. The MEMSactuated add-drop filter is implemented in IMEC's iSiPP50G silicon photonics platform and realized using a short post-processing flow to safely release the suspended MEMS structures in a wafer-level compatible process. The filter exhibits a through port linewidth of similar to 1 nm (124.37 GHz) at 1557.1 nm, and it retains a port extinction of 20 dB and a port isolation of > 50 dB under 27 V of actuation voltage. The combination of low-power consumption and a compact footprint demonstrates the suitability for very-large-scale integration in photonic circuits.
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| 34. |
- Takabayashi, Alain Y., et al.
(författare)
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Broadband Compact Single-Pole Double-Throw Silicon Photonic MEMS Switch
- 2021
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Ingår i: Journal of microelectromechanical systems. - : Institute of Electrical and Electronics Engineers (IEEE). - 1057-7157 .- 1941-0158. ; 30:2, s. 322-329
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Tidskriftsartikel (refereegranskat)abstract
- Photonic Integrated Circuits (PICs) benefit from the technology advances in the semiconductor industry to incorporate an ever-increasing number of photonic components on a single chip to create large-scale photonic integrated circuits. We here present a broadband, compact and low-loss Silicon Photonic MEMS switch based on a Single-Pole Double-Throw (SPDT) architecture, where curved electrostatic actuators mechanically displace a movable input waveguide to redirect the optical signal on chip efficiently to either of two output waveguides. The photonic switch has been fabricated in an established silicon photonics technology platform with custom MEMS release post-processing. With a compact footprint of $\mathbf 65\times 62\, \boldsymbol μ \mathbf m^\mathbf 2$ , the switch exhibits an extinction ratio exceeding 23 dB over 70 nm optical bandwidth, a low insertion loss and a fast response time below $1 μ \texts$ , meeting the requirements for integration in large-scale reconfigurable Photonic Integrated Circuits. [2020-0391]
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| 35. |
- Takabayashi, Alain Y., et al.
(författare)
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Compact Integrated Silicon Photonic Mems Power Coupler For Programmable Photonics
- 2022
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Ingår i: 2022 IEEE 35Th International Conference On Micro Electro Mechanical Systems Conference (MEMS). - : IEEE. ; , s. 216-219
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Konferensbidrag (refereegranskat)abstract
- Programmable photonics promise a plethora of optical functions while at the same time reducing the time and costs of photonic integrated circuit (PIC) development. One primary bottleneck for development of these systems is the difficulty in increasing component density because of excessive power consumption. We here present a MEMS-based Silicon Photonic power coupler that offers high optical performance (> 18 dB extinction ratio (ER), < 1.2 dB insertion loss (IL), and > 80 nm of optical bandwidth) within a compact footprint (25 mu m x 150 mu m) to provide a power-efficient active function: fast, continuous power tuning.
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| 36. |
- Takabayashi, Alain Y., et al.
(författare)
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Continuously Tunable Silicon Photonic Mems 2 X 2 Power Coupler
- 2021
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Ingår i: 2021 21St International Conference On Solid-State Sensors, Actuators and Microsystems (Transducers). - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 447-450
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Konferensbidrag (refereegranskat)abstract
- The integration of MEMS transducers in photonic integrated circuits provides opportunities for high efficiency photonic modulation and dynamic routing on-chip. We here present an electrostatically actuated, silicon photonic MEMS 2 x 2 power coupler, fabricated in IMEC's iSiPP50G platform followed by a dedicated MEMS release sequence. The in-plane, mechanical tuning mechanism provides analog power coupling between waveguides in a small form factor. With our experimental demonstration of broad, > 30 nm optical bandwidth, high extinction ratio of > 27 dB, and a low actuation voltage of only 6 V, the coupler fulfills the requirements for large-scale integration in next generation reconfigurable PICs.
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| 37. |
- Van Iseghem, Lukas, et al.
(författare)
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Low power optical phase shifter using liquid crystal actuation on a silicon photonics platform
- 2022
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Ingår i: Optical Materials Express. - : Optica Publishing Group. - 2159-3930 .- 2159-3930. ; 12:6, s. 2181-2198
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Tidskriftsartikel (refereegranskat)abstract
- Low-power and compact phase shifters are crucial for large photonic circuits, both to cope with variability and to create programmable waveguide circuits scaling to thousands of tuning elements. This work demonstrates a liquid crystal phase shifter where a lateral silicon electrode "rail" on one side of the waveguide core. Using this architecture, a strong quasi-static electric field Eactuation can be applied over the gap, which is filled with liquid crystal cladding material, with modest voltages. Because the mode is largely confined in the waveguide, optical losses are limited, compared to earlier experiments with slot waveguides. The liquid crystal is deposited locally on three different device variations using inkjet printing. The local deposition avoids unwanted interference of the liquid crystal with other optical components such as grating couplers. Measurements show similar trends as simulations of the liquid crystal orientations. For one device with a length of 50∼µm, a phase shift of almost 0.9π is shown at 10∼VRMS. We also discuss the challenges with this first demonstration of this phase shifter geometry using a silicon side-rail as an electrode.
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