| 1. |
- Anders, Berntson, et al.
(författare)
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Self-phase modulation in dispersion compensated optical fibre transmission systems
- 1996
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Ingår i: Optics Communications. - : Elsevier. - 0030-4018 .- 1873-0310. ; 130:1-3, s. 153-162
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Tidskriftsartikel (refereegranskat)abstract
- An analysis is made of the influence of self-phase modulation on optical fibre communication systems where the chromatic dispersion is compensated for by a dispersion compensation fibre. In particular we derive a simple and useful expression for the optimal fibre length in the presence of nonlinearities.
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| 2. |
- Anders, Berntson, et al.
(författare)
-
Self-phase modulation in dispersion compensated optical fibre transmission systems
- 1998
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- An analysis is made of the influence of self-phase modulation on optical fibre communication systems where the chromatic dispersion is compensated for by a dispersion compensation fibre. In particular we derive a simple and useful expression for the optimal fibre length in the presence of nonlinearities.
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| 3. |
- Anders, Berntson, et al.
(författare)
-
Self-phase modulation in dispersion-compensating systems
- 1996
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Ingår i: Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS. - : IEEE. ; , s. 405-406
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Konferensbidrag (refereegranskat)abstract
- The effects of SPM in a dispersion-compensation system are investigated. An explicit and compact formula is presented for the optimal length of the DCF. In particular, it is shown that the order of the fibers is important when SPM is considered. Using precompensation SPM effects can improve system performance. A qualitative comparison between the analytical predictions and previously presented experimental results show good agreement.
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| 4. |
- Angré, Alexander, et al.
(författare)
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Phase transformation under isostatic pressure in HIP
- 2017
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Ingår i: Powder Metallurgy. - : Informa UK Limited. - 0032-5899 .- 1743-2901. ; 60:3, s. 167-174
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Tidskriftsartikel (refereegranskat)abstract
- The new HIP cooling systems enable very fast cooling rates under isostatic pressure. This does not only enable shorter HIP cycles but also allows complete heat treatment cycles to be performed in one HIP cycle. It has been shown in previous studies that extreme pressures of several thousand bar can push phase transformation towards longer times. The new URQ HIP cooling systems give the opportunity to investigate the impact of pressures up to 2000 bar on phase transformation time dependency. For each of the two materials in this study, a comparison of austenite phase transformation time at 100 and 1700 bar was performed. The study was performed by isothermal heat treatment of specimens for a specific time followed by quenching. To evaluate the influence of pressure on hardenability, the phase fractions were evaluated using grid method on SEM images. The study found significant influence of HIP pressure on hardenability.
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| 5. |
- Arvidson, Magnus, et al.
(författare)
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FIRESAFE II Alternative fixed‑fire extinguishing systems for ro-ro spaces on ships
- 2018
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The effectiveness of ‘drencher systems’ per Resolution A.123(V) has been questioned for many years. This report presents a review of potential commercially available alternative systems and their expected performance efficiency, water consumption and estimated installation costs. Additionally, large‑scale fire tests were performed for selected systems.Three main alternative fire-extinguishing systems were identified:Compressed Air Foam Systems (CAFS)Foam-water sprinkler and foam‑water spray systems; andWater curtains.Water curtains was the least expensive system, but the areas sub‑divided by the water curtains require cargo spacing, resulting in significant yearly losses in income for a ship owner. Furthermore, water curtains were de-selected since they cannot replace a conventional fire-extinguishing system.The installation cost for the selected CAFS was very high and it gave limited fire suppression in the large‑scale fire tests, probably due to the limited discharge density of 2.4 mm/min.The system per MSC.1/Circ.1430 (10 mm/min) had superior performance while the system per Resolution A.123(V) (5 mm/min) and the foam‑water spray system (6.5 mm/min + foam) limited the fire size to some degrees. However, for a potential spill fire scenario, improvements of foam could be relevant.Foam injection could be an alternative, but no new system was recommended to be required.
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| 6. |
- Bodvik, Rasmus, et al.
(författare)
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Aggregation and network formation of aqueous methylcellulose and hydroxypropylmethylcellulose solutions.
- 2010
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Ingår i: Colloids and Surfaces A. - : Elsevier. - 0927-7757 .- 1873-4359. ; 354:1-3, s. 162-171
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Tidskriftsartikel (refereegranskat)abstract
- Solution properties of methylcellulose (MC) and hydroxypropylmethylcellulose (HPMC) have been investigated as a function of temperature and concentration using a broad range of experimental techniques. Novelties include the extensive comparison between MC and HPMC solutions as well as the combination of techniques, and the use of Cryo transmission electron microscopy (Cryo-TEM). The correlation between rheology and light scattering results clearly demonstrates the relation between viscosity change and aggregation. Cryo-TEM images show the network structures formed. Viscosity measurements show that for both MC and HPMC solutions sudden changes in viscosity occur as the temperature is increased. The onset temperature for these changes depends on polymer concentration and heating rate. For both MC and HPMC solutions the viscosity on cooling is very different compared to on heating, demonstrating the slow equilibration time. The viscosity changes in MC and HPMC solutions are dramatically different; for MC solutions the viscosity increases by several orders of magnitude when a critical temperature is reached, whereas for HPMC solutions the viscosity decreases abruptly at a given temperature, followed by an increase upon further heating. Light and (SAXS) small-angle X-ray scattering shows that the increase in viscosity, for MC as well as for HPMC solutions, is due to extensive aggregation of the polymers. Light scattering also provides information on aggregation kinetics. The SAXS measurements allow us to correlate aggregation hysteresis to the viscosity hysteresis, as well as to extract some structural information. Cryo-TEM images give novel information that a fibrillar network is formed in MC solutions, and the strong viscosity increase occurs when this network spans the whole solution volume. For HPMC solutions the behaviour is more complex. The decrease in viscosity can be related to the formation of compact objects, and the subsequent increase to formation of fibrillar structures, which are more linear and less entangled than for MC.
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| 7. |
- Czegledi, Cristian Bogdan, 1988, et al.
(författare)
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Temporal stochastic channel model for absolute polarization state and polarization-mode dispersion
- 2017
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Ingår i: 2017 Optical Fiber Communications Conference and Exhibition, OFC 2017 - Proceedings. - 2162-2701. - 9781943580231
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Konferensbidrag (refereegranskat)abstract
- We propose and validate a discrete-time channel model for the temporal drift of the absolute polarization state and polarization-mode dispersion for coherent fiber optic systems. The model can be used in simulations to test and develop DSP for coherent receivers.
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| 8. |
- Deriushkina, Ekaterina, 1992, et al.
(författare)
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Dual-Comb Swept-Wavelength Interferometry : Theory and Experiment
- 2022
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Ingår i: Journal of Lightwave Technology. - : Institute of Electrical and Electronics Engineers Inc.. - 0733-8724 .- 1558-2213. ; 40:19, s. 6508-6516
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Tidskriftsartikel (refereegranskat)abstract
- Much efforts have been put to elaborate and improve different high precision measurement schemes for characterization of advanced photonic devices and optical fibers with increasing bandwidth requirements. In light of this, swept-wavelength interferometry and dual-comb spectroscopy have been extensively applied in characterization procedures. In this paper we present in detail an experimental scheme that combines these two techniques and overcomes their limitations by using a tunable laser source in order to sweep over the frequency comb spacing and capture all intermediate frequencies. We demonstrate full-field broadband measurements over 1.25 THz comb bandwidth with increased frequency resolution, which can be performed in only 5 ms sweep. We also show that the nonlinearity of the laser sweep can be removed without an auxiliary interferometer in the setup.
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| 9. |
- Ebenhag, Sven-Christian, et al.
(författare)
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Coherent optical two-way frequency transfer in a commercial DWDM network
- 2016
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Ingår i: Proceedings of the Annual Precise Time and Time Interval Systems and Applications Meeting. - : Institute of Navigation. ; , s. 116-120, s. 116-120
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Konferensbidrag (refereegranskat)abstract
- An experimental fiber connection for ultra-stable optical frequency transfer is established between SP Technical Research Institute of Sweden in Borås and Chalmers University of Technology in Gothenburg. The distance is approximately 60 km, and the connection is implemented in the Swedish University Computer Network. The sites are connected through an active flexible communication network where each optical channel can be configured with terminal equipment based on the user needs. The network is implemented with unidirectional optical amplifiers and duplex fibers. The signal quality and the stability when sending an optical coherent frequency utilizing a wavelength in a DWDM system fiber pair, is evaluated within this work. The aim of the system is to be ultra-stable which corresponds to a stability of 10-13 for t = 1 s (Overlapping Allan Variance), as well as providing the ability to distribute monitored ultra-stable frequency with a future traceability to UTC (SP) to multiple users within the future network. This paper describes the current status and results from the frequency transfer between SP and Chalmers.
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| 10. |
- Ebenhag, Sven-Christian, et al.
(författare)
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Implementation of an optical fiber frequency distribution via commercial DWDM
- 2016
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Ingår i: 2016 IEEE International Frequency Control Symposium (IFCS). - 1075-6787. - 9781509020911
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Konferensbidrag (refereegranskat)abstract
- The rapid development in communication infrastructure over the past decades entails an increasing dependence on time and frequency, as well as its redundant distribution. This places demands not only on already existing distribution methods, but also on the development of new ones to meet future needs. To meet these demands several research groups are working on high performance fiber-based frequency transfer techniques. The best achieved performance so far is the techniques using a single bi-directional fiber connection, with customized bi-directional optical amplifiers [1]. The objective of this project is to develop a method that is compatible with data communication in DWDM-systems, i.e. using the existing infrastructure, as well as to be complementary technique for time and frequency distribution. Even though it is likely to have worse performance than the bi-directional system in terms of frequency stability, it will allow for the impassable obligation to follow the deployed structure of telecom networks. The establishment and early results of the non-stabilized link has been previously presented [2, 3]. The ongoing evaluation and improvement will be aimed at finding relevant performance specifications for a connection using this technique. The work presented here is the most recent results of the frequency transfer and discusses the future plans for the fiber connection, including the added time transfer method. If proven successful, the long-term objective is to establish a distribution network for optical frequency references in Sweden.
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