Solitonenmoleküle als Informationsträger
Final Report Abstract
The central result of this project is the demonstration of a set of four soliton-based transmission symbols. That work is built on preparatory work performed during the first project period which was finally brought to fruition and full publication in the period reported here. Two bits per clock period have been shown to be feasible in a soliton-based format; certainly a surprise to many. This is a timely contribution to the current debate about transmission formats beyond binary: Presently the data-carrying capacity of the optical fiber telecommunication network is pushed to its limits by the relentless growth of demand by society, and all recent research into this matter is about non-binary coding as the only realistic way to enhance the network’s ability. Our proposal differs from the mainstream in that it takes the fiber’s nonlinearity into account. We also note that nothing seems to preclude a combination of our technique with polarization and/or phase multiplexing techniques developed elsewhere, in order to combine the best of two research avenues into one optimized scheme. We had already begun to work on an interesting technical issue about the detection sensitivity for ultrashort pulses in the first project period. Now this work package has been finalized with good success. The new scheme avoids the accumulation of dark noise in camera pixels. It has been shown to work well: In the fairest comparison we could arrange, it improved the signal-to-noise ratio by a remarkable 34 dB. We plan to spell out this result in a publication. The results will be of interest to anyone who needs to characterize ultrashort pulses when there is not much power in them. Collision between solitons and soliton molecules are the next item to be addressed in our experiments. At the time of this reporting preliminary tests with the generation of pulses on colliding trajectories are under way, to assess the precision with which parameters can be set. The other extension is that we are now on track to introduce gain into the fiber line by the addition of an Er-doped fiber – in such a way that the dispersion allocation is only minimally disturbed. We have now acquired all necessary hardware, and we have begun to install the gain fiber and auxiliary components as suggested in the proposal. Experiments with loss-compensating gain will provide new insight into stability and noise issues. We anticipate that we can report on results from this approach in the near future.
Publications
- ,,Recent Insights about Solitons in Optical Fibers“ Nonlinear Phenomena In Complex Systems 15, 369 (2012)
F. Mitschke, A. Hause, Ch. Mahnke, P. Rohrmann
- ,,Solitons Beyond Binary: Possibility of Fibre-Optic Transmission of Two Bits per Clock Period“ Scientific Reports 2: 866 (2012)
P. Rohrmann, A. Hause, F. Mitschke
(See online at https://doi.org/10.1038/srep00866) - ,,Optimization strategies to find shapes of soliton molecules“. Applied Physics B (2013)
S. Gholami, Ph. Rohrmann, A. Hause, F. Mitschke
(See online at https://doi.org/10.1007/s00340-013-5646-4) - ,,Two-soliton and three-soliton molecules in optical fibers“. Physical Review A 87, 043834 (2013)
P. Rohrmann, A. Hause, F. Mitschke
(See online at https://doi.org/10.1103/PhysRevA.87.043834)
