| 201. |
- Karlsson, Magnus, 1967
(författare)
-
Fiber optic parametric amplifiers - properties, applications and challenges
- 2008
-
Ingår i: Conference on Quantum Electronics and Laser Science Conference on Lasers and Electro-Optics, CLEO/QELS 2008; San Jose, CA; United States; 4 May 2008 through 9 May 2008. - 9781557528599 ; , s. CWJ1-
-
Konferensbidrag (refereegranskat)abstract
- This tutorial reviews the basic properties, applications and challenges for fiber-based parametric amplifiers.
|
|
| 202. |
- Karlsson, Magnus, 1967
(författare)
-
Four-dimensional coherent signalling - Constellations and rotations
- 2014
-
Ingår i: 2014 OptoElectronics and Communication Conference, OECC 2014 and Australian Conference on Optical Fibre Technology, ACOFT 2014. - 9781922107213 ; , s. 138-140
-
Konferensbidrag (refereegranskat)abstract
- Optical coherent transmission links utilize a four-dimensional (4d) signal space. We review the search for good modulation formats in 4d, as well the properties of these formats under the (subset of all possible) 4d rotations that occur during fiber transmission.
|
|
| 203. |
- Karlsson, Magnus, 1967, et al.
(författare)
-
Four-Dimensional Optimized Constellations for Coherent Optical Transmission Systems
- 2010
-
Ingår i: 36th European Conference on Optical Communication, Turin, Italy [Invited]. - 9781424485352 ; , s. We.8.C.3-
-
Konferensbidrag (refereegranskat)abstract
- We investigate power-efficient modulation formats in the four-dimensional signal space that is used by most coherent transmission systems. The sensitivity and spectral efficiency trade-off is discussed, with and without forward error correction.
|
|
| 204. |
- Karlsson, Magnus, 1967
(författare)
-
Four-dimensional Rotations in Coherent Optical Communications
- 2014
-
Ingår i: Journal of Lightwave Technology. - : Institute of Electrical and Electronics Engineers (IEEE). - 0733-8724 .- 1558-2213. ; 32:6, s. 1246-1257
-
Tidskriftsartikel (refereegranskat)abstract
- To model electromagnetic wave propagation for coherent communications without polarization dependent losses, the unitary 2 x 2 Jones transfer matrix formalism is typically used. In this study, we propose an alternative formalism to describe such transformations based on rotations in four-dimensional (4d) Euclidean space. This formalism is usually more attractive from a communication theoretical perspective, since decisions and symbol errors can be related to geometric concepts such as Euclidean distances between points and decision boundaries. Since 4d rotations is a richer description than the conventional Jones calculus, having six rather than four degrees of freedom (DOF), we propose an extension of the Jones calculus to handle all six DOF. In addition, we show that the two extra DOF in the 4d description represents transformations that are nonphysical for propagating photons, since they does not obey the fundamental quantum mechanical boson commutation relations. Finally, we exemplify on how the nonphysical rotations can change the polarization-phase degeneracy of well-known constellations such as single-polarization QPSK, polarization-multiplexed (PM-) QPSK and polarization-switched (PS-) QPSK. For example, we show how PM-QPSK, which is well known to consist of four polarization states each having four-fold phase degeneracy, can be represented as eight states of polarizations, each with binary phase degeneracy.
|
|
| 205. |
- Karlsson, Magnus, 1967
(författare)
-
Four-wave mixing in fibers with randomly varying zero-dispersion wavelength
- 1998
-
Ingår i: Journal of the Optical Society of America B: Optical Physics. - 1520-8540 .- 0740-3224. ; 15:8, s. 2269-2275
-
Tidskriftsartikel (refereegranskat)abstract
- The effect of random fluctuations in the zero-dispersion wavelength is considered for fiber four-wave mixing. Theoretical expressions for average parametric gain, phase-conjugation conversion efficiency, and gain bandwidth are obtained and found to be in good agreement with experiments. Possible limitations on the noise figure in phase-sensitive amplifiers based on fiber four-wave mixing are also discussed.
|
|
| 206. |
- Karlsson, Magnus, 1967, et al.
(författare)
-
Generalized pulse-position modulation for optical power-efficient communication
- 2011
-
Ingår i: European Conference and Exhibition on Optical Communication - Proceedings. - 2162-2701. - 9781557529312
-
Konferensbidrag (refereegranskat)abstract
- A family of modulation formats is derived by combining pulse-position modulation (PPM) with multilevel dual-polarization signal constellations. With 16-PPM, gains of up to 5.4 dB are obtained over dual-polarization QPSK, at the cost of reduced spectral efficiency.
|
|
| 207. |
- Karlsson, Magnus, 1967
(författare)
-
Geometrical interpretation of second-order PMD
- 2006
-
Ingår i: Journal of Lightwave Technology. - 0733-8724 .- 1558-2213. ; 24:1, s. 643 - 51
-
Tidskriftsartikel (refereegranskat)abstract
- A geometrical interpretation of second-order polarization mode dispersion (SOPMD) as the curved three-dimensional (3-D) area swept by the PMD vector as it increases with propagation in a birefringent system is introduced. The depolarization and polarization-dependent chromatic dispersion parts of the SOPMD can be viewed as projections of this area in orthogonal directions. This interpretation enables us to translate the problem of maximizing the SOPMD in, e.g., PMD emulators and programmable PMD sources to an isoperimetric problem, i.e., a problem of maximizing the area enclosed by a given perimeter, which has well-known solutions. Both the discrete problems corresponding to a set of birefringent wave plates are discussed, and the continuous problem in which an arbitrary birefringent medium is considered. Analytic formulas are derived for the first time for the maximum SOPMD, depolarization, and polarization-dependent chromatic dispersion that can be realized in PMD emulators
|
|
| 208. |
- Karlsson, Magnus, 1967, et al.
(författare)
-
Geometrically induced non-linear phenomena of the TE11-mode in a rectangular optical waveguide
- 1995
-
Ingår i: Physica Scripta. - : IOP Publishing. - 1402-4896 .- 0031-8949. ; 52:3, s. 313-317
-
Tidskriftsartikel (refereegranskat)abstract
- Retaining all significant terms of Maxwell equations, we derive a gener-alized governing equation for waves in a Kerr-nonlinear, rectangulai optical waveguide. As a specific example, we show that the field com-ponents of the TEn-mode in such a waveguide will achieve oscillations in both amplitude and phase during propagation. The nonlinearity appeal only in a characteristic length scale of these phenomena, whereas tht overall properties of the oscillations are determined by the waveguidt geometry.
|
|
| 209. |
- Karlsson, Magnus, 1967, et al.
(författare)
-
High-speed OTDM and impact of PMD
- 1999
-
Ingår i: 1999 IEEE LEOS Annual Meeting Conference Proceedings. LEOS'99. 12th Annual Meeting. IEEE Lasers and Electro-Optics Society 1999 Annual Meeting. - 0780356349
-
Konferensbidrag (refereegranskat)abstract
- We discuss the impact of polarization mode dispersion (PMD) in high-speed fiber transmission. Special emphasis is put on PMD compensation techniques, and their intrinsic limitations. We also propose a new and simple distributed compensation scheme.
|
|
| 210. |
- Karlsson, Magnus, 1967, et al.
(författare)
-
Higher order polarization mode dispersion compensator with three degrees of freedom
- 2001
-
Ingår i: Optical Fiber Communication Conference and International Conference on Quantum Information. - 1557526540
-
Konferensbidrag (refereegranskat)abstract
- We compare several PMD compensation methods, and find that the simple PMD compensator with a variable polarization controller (PC) and a variable time delay line can compensate for not only first, but also higher order PMD.
|
|
