| 1. |
- Abul-Kasim, Kasim, et al.
(författare)
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Intradural spinal tumors: current classification and MRI features
- 2008
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Ingår i: Neuroradiology. - : Springer Science and Business Media LLC. - 1432-1920 .- 0028-3940. ; 50:4, s. 301-314
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Tidskriftsartikel (refereegranskat)abstract
- The differential diagnosis of intradural spinal tumors is primarily based on location, but the clinical presentation, age, and gender of the patient are also important factors in determining the diagnosis. This comprehensive review focuses on the current classification, clinical symptoms, and MRI features of the more common intradural extramedullary and intramedullary neoplastic lesions. This review does not include extradural lesions.
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| 2. |
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| 3. |
- Bernabé, S., et al.
(författare)
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Highly integrated VCSEL-based 10Gb/s miniature optical sub-assembly
- 2005
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Ingår i: Proceedings - Electronic Components and Technology Conference. - Lake Buena Vista, FL : IEEE. ; , s. 1333-1338
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Konferensbidrag (refereegranskat)abstract
- In order to fit with the present and future needs of the Datacom transceiver market, newly designed high rate transmitter optical subassemblies (TOSAs) have to be compact, low cost and compatible with mass production. We propose here an innovative design strategy that reaches all these targets by integrating a 10Gbps 850nmVCSEL laser diode and its laser driver with other functionalities (e.g. power monitoring and thermal monitoring) in a small form factor package. Taking advantages of the optical properties of the VCSEL and using flip-chip techniques, the transmitter exhibits excellent hyperfrequency performances and compatibility with mass production due to the use of collective manufacturing technologies and passive optical alignment. This versatile approach is also applicable to high rate receivers, parallel optics emitters, and singlemode low cost transmitter integrating long wavelength VCSELs.
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| 4. |
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| 5. |
- Gilet, Ph., et al.
(författare)
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1.3 μm VCSELs : InGaAs/GaAs, GaInNAs/GaAs multiple quantum wells and InAs/GaAs quantum dots- Three candidates as active material
- 2007
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Ingår i: Vertical - Cavity Surface - Emitting Lasers XI. - San Jose, CA : SPIE. ; , s. F4840-F4840
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Konferensbidrag (refereegranskat)abstract
- In this article, we report our results on 1.3ÎŒm VCSELs for optical interconnection applications. Room temperature continuous-wave lasing operation is demonstrated for top emitting oxide-confined devices with three different active materials, highly strained InGaAs/GaAs(A) and GalnNAs/GaAs (B) multiple quantum wells (MQW) or InAs/GaAs (C) quantum dots (QD). Conventional epitaxial structures grown respectively by Metal Organic Vapour Phase Epitaxy (MOVPE), Molecular Beam Epitaxy (MBE) and MBE, contain rully doped GaAs/AlGaAs DBRs. All three epilayers are processed in the same way. Current and optical confinement are realized by selective wet oxidation. Circular apertures from 2 ÎŒm to 16 ÎŒm diameters are defined. At room temperature and in continuous wave operation, all three systems exhibit lasing operation at wavelengths above 1 275nm and reached 1 300nm for material (A). Typical threshold currents are in the range [1-10]mA and are strongly dependent firstly on oxide diameter and secondly on temperature. Room temperature cw maximum output power corresponds respectively to 1.77mW, 0.5mW and 0.6mW. By increasing driving current, multimode operation occurs at different level depending on the oxide diameter. In case (A), non conventional modal behaviors will be presented and explained by the presence of specific oxide modes. Thermal behaviors of the different devices have been compared. In case (A) and (C) we obtain a negative T0. We will conclude on the different active materials in terms of performances with respect to 1300nm VCSEL applications.
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| 6. |
- Hammar, Mattias, et al.
(författare)
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1.3-mu m InGaAs vertical-cavity surface-emitting lasers
- 2005
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Ingår i: 2005 IEEE LEOS Annual Meeting Conference Proceedings (LEOS). - 0780392175 ; , s. 396-397
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Konferensbidrag (refereegranskat)abstract
- We report on the fabrication and performance of N-free InGaAs/GaAs 1.3-mu m range vertical-cavity surface-emitting lasers (VCSELs). Using optimized quantum-well (QW) growth conditions in combination with negative gain-cavity tuning, high-performance VCSELs with emission wavelength up to 1300 nm are realized. The performance figures include mA-range threshold currents, mW-range singlemode output power, continuous-wave operation up to 140 degrees C and 10 Gbit/s data transmission.
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| 7. |
- Pougeoise, E., et al.
(författare)
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1.3 ÎŒm strained InGaAs quantum well VCSELs : Operation characteristics and transverse modes analysis
- 2006
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Ingår i: Vertical-Cavity Surface-Emitting Lasers X. - San Jose, CA : SPIE. ; , s. 13207-13207
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Konferensbidrag (refereegranskat)abstract
- We report results on strained InGaAs quantum well Vertical Cavity Surface Emitting Lasers (VCSELs) for optical interconnection applications. The structure was grown by metalorganic vapour-phase epitaxy (MOVPE) and processed as top p-type DBR oxide-confined device. Our VCSELs exhibit low threshold currents and deliver up to 1.77 mW in continuous wave operation at room temperature. Fundamental mode continuous-wave lasing at wavelengths beyond 1300 nm is demonstrated at room temperature. The thermal behaviour of our devices is explained through the threshold current-temperature characteristics. Furthermore, the effective index model is used to understand the modal behaviour.
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| 8. |
- Pougeoise, E., et al.
(författare)
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Experimental characteristics and analysis of transverse modes in 1.3 μm strained InGaAs quantum well VCSELs
- 2006
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Ingår i: Proc SPIE Int Soc Opt Eng. - : SPIE. - 0819462411 - 9780819462411
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Konferensbidrag (refereegranskat)abstract
- In the context of optical interconnection applications, we report on results obtained on strained InGaAs quantum well Vertical Cavity Surface Emitting Lasers (VCSELs). Our devices are top p-type DBR oxide-confined VCSEL, grown by metalorganic vapour-phase epitaxy (MOVPE). These lasers exhibit low threshold currents and deliver up to 1.77 mW in continuous wave operation at room temperature. Fundamental mode continuous-wave lasing at wavelengths beyond 1300 nm at room temperature is reached for a 4 μm oxide diameter VCSEL. The particular design of the active layer based on a large detuning between the gain maximum and the cavity resonance gives our devices a very specific thermal and modal behaviour. Therefore, we study the spectral and spatial distributions of the transverse modes by near field scanning optical microscopy using a micropolymer tip at the end of an optical fibre.
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| 9. |
- Pougeoise, E., et al.
(författare)
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Experimental study of the lasing modes of 1.3-ÎŒm highly strained InGaAs-GaAs quantum-well oxide-confined VCSELs
- 2009
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Ingår i: IEEE Photonics Technology Letters. - 1041-1135 .- 1941-0174. ; 21:6, s. 377-379
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Tidskriftsartikel (refereegranskat)abstract
- We present an experimental study of the main modes involved in the emission properties of InGaAs-GaAs quantum-well oxide-confined long wavelength vertical-cavity surface-emitting lasers. Lasing properties are dominated by the so-called "oxide modes" and by aperture modes, respectively, for small and large driving currents. We present complementary investigations of the laser emission including far-field angular distribution and spectroscopic near-field optical microscopy to a better understanding of the nature of the "oxide modes."
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| 10. |
- Pougeoise, E., et al.
(författare)
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Strained InGaAs quantum well vertical cavity surface emitting lasers emitting at 1.3 mu m
- 2006
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Ingår i: Electronics Letters. - : Institution of Engineering and Technology (IET). - 0013-5194 .- 1350-911X. ; 42:10, s. 584-586
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Tidskriftsartikel (refereegranskat)abstract
- Results on strained InGaAs quantum well vertical cavity surface emitting lasers for optical interconnection applications are reported. Fundamental mode continuous-wave lasing at wavelengths beyond 1300 nm is demonstrated at room temperature. The metal-organic vapour-phase epitaxy grown structure was processed as top p-type distribute Bragg reflector oxide-confined devices.
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| 11. |
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| 12. |
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| 13. |
- Sundgren, Petrus, et al.
(författare)
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Highly strained InGaAs/GaAs multiple quantum-wells for laser applications in the 1200-1300-nm wavelength regime
- 2005
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 87:7, s. 071104-
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Tidskriftsartikel (refereegranskat)abstract
- We report on metalorganic vapor-phase epitaxy growth optimization and properties of highly strained InGaAs/GaAs quantum-well (QW) structures with emission wavelength beyond 1200 nm. It is observed that a sufficiently high V/III ratio in combination with low growth temperature is critical for preserved layer integrity when increasing the strain. Multiple QWs with up to five wells are realized without any degradation in photoluminescence intensity or broad-area laser performance at an emission wavelength of 1240 nm with threshold current density below 70 A/cm(2) per well.
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| 14. |
- Zakhary, Mina M., et al.
(författare)
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Prevalence and Etiology of Intracranial Hemorrhage in Term Children Under the Age of Two Years: A Retrospective Study of Computerized Tomographic Imaging and Clinical Outcome in 798 Children
- 2009
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Ingår i: Academic Radiology. - : Elsevier BV. - 1878-4046 .- 1076-6332. ; 16:5, s. 572-577
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Tidskriftsartikel (refereegranskat)abstract
- Rationale and Objectives. The purposes of this study were to retrospectively identify various etiologies underlying intracranial hemorrhages (ICHs) in term infants aged <2 years and their respective prevalence in this population and to describe the long-term clinical outcomes in these patients. Materials and Methods. A retrospective review of the medical records and computed tomographic studies of the head in 798 term infants aged 0 to 24 months with suspected or known ICHs was conducted. Results. ICHs were present in 195 of the 798 infants (24%). More than one type of ICH was present in 32%. Subdural hemorrhage was the most frequent type of ICH, occurring in 63% of the infants. Good clinical outcomes were present in 49% of the infants but varied depending on the location, etiology, and timing of the ICH. Conclusion. The incidence of various etiologies of ICH depended on the ages of the infants. The overall clinical outcomes were good, with no long-term sequelae in half of the infants presenting with ICHs. In infants aged >4 weeks presenting with ICHs, special attention should be given to the possibility of nonaccidental trauma etiology, because this is common and has worse long-term outcomes.
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