| 1. |
- Benisty, H., et al.
(författare)
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Low-loss photonic-crystal and monolithic InP integration : Bands, bends, lasers, filters
- 2004
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Ingår i: Photonic Crystal Materials and Devices II. - : SPIE - International Society for Optical Engineering. - 0819452688 ; , s. 119-128
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Konferensbidrag (refereegranskat)abstract
- Practical realizations of 2D (planar) photonics crystal (PhC) are either on a membrane or etched through a conventional heterostructure. While fascinating objects can emerge from the first approach, only the latter approach lends itself to a progressive integration of more compact PhC's towards monolithic PICs based on InP. We describe in this talk the various aspects from technology to functions and devices, as emerged from the European collaboration "PCIC". The main technology tour de force is deep-etching with aspect ratio of about 10 and vertical sidewall, achieved by three techniques (CAIBE, ICP-RIE, ECR-RIE). The basic functions explored are bends, splitters/combiners, mirrors, tapers, and the devices are filters and lasers. At the end of the talk, I will emphasize some positive aspects of "broad" multimode PhC waveguides, in view of compact add-drop filtering action, notably.
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| 2. |
- Talneau, A., et al.
(författare)
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Compound cavity measurement of transmission and reflection of a tapered single-line photonic-crystal waveguide
- 2003
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 82:16, s. 2577-2579
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Tidskriftsartikel (refereegranskat)abstract
- Measurements on a single-line defect photonic crystal waveguide demonstrate propagation losses as low as 140 cm(-1) and coupling efficiency to a ridge access guide increased from 20% to 50% thanks to a tapered access. These results are obtained by analyzing the internal cavities created by residual reflections, hence, requiring a single sample. They are nevertheless crosschecked by measurements on distinct samples by the Fabry-Perot resonance method.
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| 3. |
- Talneau, A., et al.
(författare)
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High-bandwidth transmission of an efficient photonic-crystal mode converter
- 2004
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Ingår i: Optics Letters. - 0146-9592 .- 1539-4794. ; 29:15, s. 1745-1747
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Tidskriftsartikel (refereegranskat)abstract
- We have investigated both theoretically and experimentally the spectral behavior and the transmission and reflection performance of a photonic-crystal (PhC) mode converter upon an InP substrate. This taper exhibits 70% transmission efficiency on an 80-nm bandwidth when it couples a ridge access guide to a strongly confined single-missing-row PhC guide. Such a taper design included in a PhC bend contributes a large benefit to the overall transmission budget of the PhC-based link.
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| 4. |
- Wessberg, Johan, 1962, et al.
(författare)
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Real-time prediction of hand trajectory by ensembles of cortical neurons in primates.
- 2000
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 408:6810, s. 361-5
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Tidskriftsartikel (refereegranskat)abstract
- Signals derived from the rat motor cortex can be used for controlling one-dimensional movements of a robot arm. It remains unknown, however, whether real-time processing of cortical signals can be employed to reproduce, in a robotic device, the kind of complex arm movements used by primates to reach objects in space. Here we recorded the simultaneous activity of large populations of neurons, distributed in the premotor, primary motor and posterior parietal cortical areas, as non-human primates performed two distinct motor tasks. Accurate real-time predictions of one- and three-dimensional arm movement trajectories were obtained by applying both linear and nonlinear algorithms to cortical neuronal ensemble activity recorded from each animal. In addition, cortically derived signals were successfully used for real-time control of robotic devices, both locally and through the Internet. These results suggest that long-term control of complex prosthetic robot arm movements can be achieved by simple real-time transformations of neuronal population signals derived from multiple cortical areas in primates.
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| 5. |
- Zimmermann, J, et al.
(författare)
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Photonic crystal waveguides with propagation losses in the 1 dB/mm range
- 2004
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Ingår i: Journal of Vacuum Science & Technology B. - : American Vacuum Society. - 1071-1023 .- 1520-8567. ; 22:6, s. 3356-3358
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Tidskriftsartikel (refereegranskat)abstract
- High-quality photonic crystal waveguides have been fabricated in the InGaAsP/InP and GaAs/AlGaAs material systems aimed at the communication wavelengths of 1.55 and 1.31 mum. The waveguides consist of omitted rows of holes in a triangular lattice of air holes etched into the semiconductor heterostructures by electron cyclotron resonance reactive ion etching. Efficient waveguiding has been observed in optical transmission measurements, with waveguide losses ranging from 1.5 dB/mm for a waveguide with three missing row of holes (W3) to 0.2 dB/mm for seven missing rows (W7). (C) 2004 American Vacuum Society.
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