| 1. |
- Xu, Tianhua, et al.
(författare)
-
Analysis of chromatic dispersion compensation and carrier phase recovery in long-haul optical transmission system influenced by equalization enhanced phase noise
- 2017
-
Ingår i: Optik (Stuttgart). - : Elsevier GmbH. - 0030-4026 .- 1618-1336. ; 138, s. 494-508
-
Tidskriftsartikel (refereegranskat)abstract
- The performance of long-haul coherent optical fiber transmission system is significantly affected by the equalization enhanced phase noise (EEPN), due to the interaction between the electronic dispersion compensation (EDC) and the laser phase noise. In this paper, we present a comprehensive study on different chromatic dispersion (CD) compensation and carrier phase recovery (CPR) approaches, in the n-level phase shift keying (n-PSK) and the n-level quadrature amplitude modulation (n-QAM) coherent optical transmission systems, considering the impacts of EEPN. Four CD compensation methods are considered: the time-domain equalization (TDE), the frequency-domain equalization (FDE), the least mean square (LMS) adaptive equalization are applied for EDC, and the dispersion compensating fiber (DCF) is employed for optical dispersion compensation (ODC). Meanwhile, three carrier phase recovery methods are also involved: a one-tap normalized least mean square (NLMS) algorithm, a block-wise average (BWA) algorithm, and a Viterbi-Viterbi (VV) algorithm. Numerical simulations have been carried out in a 28-Gbaud dual-polarization quadrature phase shift keying (DP-QPSK) coherent transmission system, and the results indicate that the origin of EEPN depends on the choice of chromatic dispersion compensation methods, and the effects of EEPN also behave moderately different in accordance to different carrier phase recovery scenarios.
|
|
| 2. |
- Xu, T., et al.
(författare)
-
Analytical estimation in differential optical transmission systems influenced by equalization enhanced phase noise
- 2016
-
Ingår i: 2016 Progress In Electromagnetics Research Symposium, PIERS 2016 - Proceedings. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781509060931 ; , s. 4844-4848
-
Konferensbidrag (refereegranskat)abstract
- An analytical model is presented for assessing the performance of the bit-error-rate (BER) in the differential m-level phase shift keying (m-PSK) transmission systems, where the influence of equalization enhanced phase noise (EEPN) has been considered. Theoretical analysis has been carried out in differential quadrature phase shift keying (DQPSK), differential 8-PSK (D8PSK), and differential 16-PSK (D16PSK) optical transmission systems. The influence of EEPN on the BER performance, in term of signal-to-noise ratio (SNR), are investigated for different fiber dispersion, LO laser linewidths, symbol rates, and modulation formats. Our analytical model achieves a good agreement with previously reported EEPN induced BER floors, and can give an accurate prediction for the DQPSK system, and a leading-order approximation for the D8PSK and the D16PSK systems.
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
- Rouhi, Mohammad, et al.
(författare)
-
Effects of manufacturing on the structural performance of composites in vacuum assisted resin transfer molding
- 2023
-
Ingår i: Journal of reinforced plastics and composites (Print). - : SAGE Publications Ltd. - 0731-6844 .- 1530-7964. ; 42, s. 264-
-
Tidskriftsartikel (refereegranskat)abstract
- This work focuses on developing a seamlessly integrated modeling platform for manufacturing, designing, and analyzing fiber-reinforced composite structures. The manufacturing method is vacuum assisted resin transfer molding, and the analysis method is the finite element method. The unique integration of two commercial software (Moldex3D and ABAQUS) with additional interfaces and physics-based micromechanics enables variabilities during the manufacturing to be directly embedded into the structural analysis. The manufacturing output is the resin pressure which is used to predict the compaction pressure and calculate local fiber volume fractions. The predicted non-uniform volume fractions provide local mechanical properties allowing seamless transfer of process effects and properties variability to the final structural analysis. Three demonstrators are presented as examples for simulation and validation against experiments, both in manufacturing and structural performance. The results show very good agreement between simulations and experiments regarding resin flow times and measurements (within 17%) and demonstrators’ structural stiffness (within 15%). © The Author(s) 2022.
|
|
| 7. |
- Rubin, T., et al.
(författare)
-
Thermodynamic effects in a gas modulated Invar-based dual Fabry-Pérot cavity refractometer
- 2022
-
Ingår i: Metrologia. - : IOP Publishing Ltd. - 0026-1394 .- 1681-7575. ; 59:3
-
Tidskriftsartikel (refereegranskat)abstract
- By measuring the refractivity and the temperature of a gas, its pressure can be assessed from fundamental principles. The highest performing instruments are based on Fabry-Perot cavities (FPC). Gas modulation refractometry (GAMOR) is a methodology that has the ability to reduce the influence of disturbances to such an extent that high-precision (sub-parts-per-million) assessments of pressure can be made by the use of FPCs of Invar. To allow for high accuracy assessments, it is of importance to assess the uncertainty contribution from the thermodynamic effects that are associated with the gas filling and emptying of the cavity (pV-work). This paper presents a detailed scrutiny of the influence of the gas exchange process on the assessment of gas temperature on an Invar-based dual-FPC (DFPC) instrumentation. It is shown that by virtue of a combination of a number of carefully selected design entities (a small cavity volume with a bore radius of 3 mm, a spacer material with high heat capacitance, large thermal conductivity, and no regions that are connected with low thermal conductance, i.e. no heat islands, and a continuous assessment of temperature of the cavity spacer) the system is not significantly affected by pV-work. Simulations show that 10 s after the filling all temperature gradients in the system are well into the sub-mK range. Experiments support that refractivity assessments initiated after 40 s are not significantly affected by the pV-work. The analysis given in this work indicates that an upper limit for the influence of pV-work on the Invar-based DFPC system using 100 s long gas modulation cycles is 0.5 mK/100 kPa (or 1.8 ppm/100 kPa). Consequently, thermodynamic effects will not be a limiting factor when the Invar-based DFPC GAMOR system is used for assessments of pressure or as a primary pressure standard up to atmospheric pressures.
|
|
| 8. |
- Zhybak, Mykhailo T., et al.
(författare)
-
Direct detection of ammonium ion by means of oxygen electrocatalysis at a copper-polyaniline composite on a screen-printed electrode
- 2016
-
Ingår i: Microchimica Acta. - : Springer Science and Business Media LLC. - 0026-3672 .- 1436-5073. ; 183:6, s. 1981-1987
-
Tidskriftsartikel (refereegranskat)abstract
- We describe a composite material for use in electrochemical oxygen reduction. A screen-printed electrode (SPE) was consecutively modified with electrodeposited copper, a Nafion membrane and electropolymerized polyaniline (PANi) to give an electrocatalytic composite of type PANi/Nafion/Cu2O/SPE that displays good electrical conductivity at neutral pH values. It is found that the presence of ammonia causes complex formation with Cu(I), and this causes electroreduction of oxygen to result in an increased cathodic current. The finding was applied to the quantification of ammonium ions in the 1 to 1000 μM concentration range by amperometry at −0.45 V (vs. Ag/AgCl). This Faradaic phenomenon offers the advantage of direct voltammetric detection, one of the lowest known limits of detection (0.5 μM), and high sensitivity (250 mA∙M−1∙cm−2). It was applied to the determination of ammonium ion in human serum where it compared well with the photometric routine approach for clinical analysis using glutamate dehydrogenase. [Figure not available: see fulltext.]
|
|
