| 1. |
- Eriksson, Tobias, 1986, et al.
(författare)
-
Four-Dimensional Estimates of Mutual Information in Coherent Optical Communication Experiments
- 2015
-
Ingår i: European Conference on Optical Communications (ECOC), Valencia, Spain, 27 September - 1 October 2015. - 9788460817413
-
Konferensbidrag (refereegranskat)abstract
- Mutual information is experimentally investigated for long-haul coherent transmission. Receivers that consider memoryless four-dimensional noise distributions can achieve significantly higher rates than receivers assuming two-dimensional symmetric distributions.
|
|
| 2. |
- Eriksson, Tobias, 1986, et al.
(författare)
-
Impact of 4D Channel Distribution on the Achievable Rates in Coherent Optical Communication Experiments
- 2016
-
Ingår i: Journal of Lightwave Technology. - 0733-8724 .- 1558-2213. ; 34:9, s. 2256-2266
-
Tidskriftsartikel (refereegranskat)abstract
- We experimentally investigate mutual information and generalized mutual information for coherent optical transmission systems. The impact of the assumed channel distribution on the achievable rate is investigated for distributions in up to four dimensions. Single channel and wavelength division multiplexing (WDM) transmission over transmission links with and without inline dispersion compensation are studied. We show that for conventional WDM systems without inline dispersion compensation, a circularly symmetric complex Gaussian distribution is a good approximation of the channel. For other channels, such as with inline dispersion compensation, this is no longer true and gains in the achievable information rate are obtained by considering more sophisticated four-dimensional (4D) distributions. We also show that for nonlinear channels, gains in the achievable information rate can also be achieved by estimating the mean values of the received constellation in four dimensions. The highest gain for such channels is seen for a 4D correlated Gaussian distribution.
|
|
| 3. |
- Fehenberger, Tobias, et al.
(författare)
-
Experimental Analysis of Correlations in the Nonlinear Phase Noise in Optical Fiber Systems
- 2016
-
Ingår i: ECOC 2016; 42nd European Conference on Optical Communication. ; :W.1.D.4, s. 488-490
-
Konferensbidrag (refereegranskat)abstract
- A dual-link self-homodyne receiver is used to measure the phase correlations introduced bythe interplay of dispersion and fiber nonlinearities. The dependence of the memory on the WDM setup,signal power and transmission distance is experimentally demonstrated.
|
|
| 4. |
|
|
| 5. |
- Fehenberger, Tobias, et al.
(författare)
-
On the impact of carrier phase estimation on phase correlations in coherent fiber transmission
- 2015
-
Ingår i: 2015 Tyrrhenian International Workshop on Digital Communications, TIWDC 2015. - 9781467392600 ; , s. 35-38
-
Konferensbidrag (refereegranskat)abstract
- Carrier phase estimation (CPE) is an integral part of the digital signal processing (DSP) of coherent optical communication systems as it compensates laser phase noise (LPN) introduced by free-running transmitter and local oscillating (LO) lasers. Nonlinear interactions during propagation are another source of correlated phase noise. In this paper, we show through simulations and in experiments that blind decision-directed (DD) CPE with regular block lengths removes a large portion of the memory. This makes it virtually impossible in practice to quantify correlations that come from propagation effects, or to obtain rate gains by exploiting the nonlinear phase noise (NLPN). Larger CPE block lengths leave the memory partly intact. This, however, comes at the expense of reduced information rates. We are able to fully recover this rate loss in simulations by using idealized processing of phase distortions. In experiments with full DSP, an almost full rate recovery is reported.
|
|
