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| 3. |
- Djupsjöbacka, Anders, et al.
(författare)
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Estimating Eye-opening Penalty with Aid of the Ripple Function of Fiber Bragg-gratings
- 2007
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Ingår i: Journal of Optical Communications. ; 28, s. 91-95
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Tidskriftsartikel (refereegranskat)abstract
- We investigate six different methods presented in litera-ture to estimate eye-opening penalty for dispersion-com-pensating fiber Bragg gratings with aid of the grating’s ripple function. The investigation is based on theoretical ripple functions as well on measurement results of three continuously chirped gratings. The gratings in question offer full wavelength coverage between 1530 nm and 1565 nm. We will show that the eye-opening penalty de-pends on the phase and frequency of the grating’s ripple function as well as to pattern length and to pulse form of the signal used. Since the estimation methods do not ac-count for these properties, their accuracy is shown to be limited.
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| 4. |
- Djupsjöbacka, Anders, et al.
(författare)
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Measured Temporal statistics of the DGD RMS-Value in Buried Optical Fibers
- 2009
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Ingår i: IEEE Photonics Technology Letters. - 1041-1135 .- 1941-0174. ; 21:24, s. 1801-1803
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Tidskriftsartikel (refereegranskat)abstract
- The behavior of the differential group delay (DGD)root-mean-square (rms) value is investigated for a buried G.652fiber line in a metropolitan fiber plant outside Stockholm, Sweden.This study presents measurement results from two different mea-surement periods where the same fiber and the same measurementequipment was used. In total,2800 hours of measurements wereperformed. As expected, the recorded DGD rms-value variedwith time. The measured standard deviation for the statistics ofthe DGD rms-value fits reasonably well with values presentedin literature. The fiber line, which showed a DGD rms-value of0.45 ps in average, had an extremely long time constant. Evenafter2800 hours of measurements we have not closed in on theexpected asymptotic distribution of the measured DGD rms-value
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| 5. |
- Ekelund, Maria, 1970-
(författare)
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Psoriasis and Temporomandibular Joint Involvement in Juvenile Idiopathic Arthritis (JIA) : A Longitudinal Study of the Nordic JIA Cohort
- 2020
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Juvenile idiopathic arthritis, JIA, is used as an umbrella term covering a heterogeneous group of chronic arthritis forms in children, many of which have important differences compared to adult arthritis, while others possibly represent similar diseases among children and adults. Classification aims to give a better understanding of the pathogenesis, patterns, disease trajectories and treatment responses. For the juvenile psoriatic arthritis, JPsA, the classification criteria are currently being debated. The distribution of affected joints in JIA differs greatly and it is unknown why some joints appear to be more affected than others. The temporomandibular joint (TMJ) can be affected early in the course of the disease and often the symptoms are mild and without obvious swelling.This thesis has its origin in the Nordic Study Group of Paediatric Rheumatology and the population-based prospective study of 510 children with newly diagnosed JIA included between 1997 and 1999. Totally 440 children were included in the eight-year follow-up, and in the TMJ study 265 patients were examined and underwent cone-beam computed tomography, CBCT, 17 years after onset.After eight years a considerable proportion of the children with definite psoriasis were classified as undifferentiated JIA based on the exclusion criteria in the ILAR classification. Our data also presents the heterogenicity of JPsA and the development over time of clinical variables supporting a psoriatic diathesis, as well as the overlap between JPsA and enthesitis-related arthritis in a group of patients. We found that extensive symptoms and dysfunctions of the TMJ are seen in JIA 17 years after disease onset, even in patients registered with inactive disease or remission. Individuals with substantial condylar damage on CBCT were found in all JIA categories. The deeper understanding of a chronic disease over time is crucial for research initiatives to improve care as well as for clinical decisions and planning of the health care.Our findings suggest a need for a more appropriate classification of JPsA and also that aspects of TMJ involvement should be included in the general health assessment in JIA.
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- Forzati, Marco, et al.
(författare)
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40-gb/s field transmission through 540 km ssmf using the aprz modulation format
- 2005
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Ingår i: Optics InfoBase Conference Papers. - : Optical Society of America. - 1557527849 - 9781557527844
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Konferensbidrag (refereegranskat)abstract
- We report the first field transmission experiment using the APRZ modulation format for 40-Gb/s transmission through 540 km SSMF, which confirms the improved nonlinear tolerance of APRZ. The optimum phase-modulation amplitude in this experiment is p/2.
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| 8. |
- Forzati, Marco, et al.
(författare)
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Asynchronous Phase Modulation for the Suppression of IFWM
- 2007
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Ingår i: IEEE transactions on intelligent transportation systems (Print). - 1524-9050 .- 1558-0016. ; 25, s. 2969-75
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Tidskriftsartikel (refereegranskat)abstract
- Intrachannel four-wave mixing (IFWM) represents main source of impairments in fiber transmission at 40 Gb/s. A number of phase modulation techniques have been proposed to suppress the IFWM. In this paper, we study a cost-effective way of increasing the nonlinear tolerance of a 40-Gb/s wavelength division multiplexing transmission system by asynchronous phase modulation (APM). This can be achieved with one phase modulator placed after the wavelength multiplexer so that cost is shared by all channels. We show, by means of numerical simulations and laboratory experiments, that APM greatly improves the performance of ON-OFF-keying transmission.
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| 10. |
- Forzati, Marco, et al.
(författare)
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Reduction of intra-channel four-wave mixing using the alternate-phase RZ modulation format
- 2002
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Ingår i: IEEE Photonics Technology Letters. - 1041-1135 .- 1941-0174. ; 14:9
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Tidskriftsartikel (refereegranskat)abstract
- —The authors propose a modulation format in which the phase of the signal pulses alternates, in order to reduce the intrachannel four-wave mixing. They demonstrate numerically that the performance of a 40-Gb/s transmission link can be substantially improved.
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