Study of the operating regime for all-optical passive 2Rregeneration of dispersion-managed RZ data at 40 Gb/s using in-lineNOLMs

In this letter, we numerically demonstrate that the use of inline nonlinear optical loop mirrors in strongly dispersion-managed transmission systems dominated by pulse distortion and amplitude noise can achieve all-optical passive 2R regeneration of a 40-Gb/s return-to-zero data stream. We define the tolerance limits of this result to the parameters of the input pulses     

Numerical estimate of BER in optical systems with strong patterningeffects

A statistical approach to numerical evaluation of bit error rates in optical transmission systems with strong patterning effects is described. As an example, a specific dispersion-managed WDM (40 Gbit/s per channel) system using transmission with large bit overlapping was examined     

Impact of design of sharp non-uniform fibre Bragg gratings on system performance

A simple design of non-uniform fibre Bragg grating (FBG) with sharp reflection and low dispersion is proposed. The impact of different design solutions for ultra-square FBG-based filters on transmission system performance is investigated.     

The multiple-scale averaging and dynamics of dispersion-managed optical solitons

Multiple-scale averaging is applied to the nonlinear Schrödinger equation with rapidly varying coefficients, and use the results to analyze pulse propagation in an optical fiber when a periodic dispersion map is employed. The effects of fiber loss and repeated amplification are taken into account by use of a coordinate transformation to relate the pulse dynamics in lossy fibers to that in equivalent lossless fibers. Second-order averaging leads to a general evolution equation that is applicable to both return-to-zero (soliton) and non-return-to-zero encoding schemes. The resulting equation is then applied to the specific case of solitons, and an asymptotic theory for the pulse dynamics is developed. Based upon the theory, a simple and effective design of two-step dispersion maps that are advantageous for wavelength-division-multiplexed soliton transmission is proposed. Theuse of these specifically designed dispersion maps allows simultaneous minimization of dispersive radiation in several different channels.     

Cascaded optical communication systems with in-line semiconductoroptical amplifiers

The optimization of the performance of installed standard-monomode fibers based optical transmission systems with in-line semiconductor optical amplifiers (SOA's) is reported in this paper. Both solitons and nonreturn-to-zero (NRZ) signals are studied and their capacities are compared. This investigation is based on numerical simulations by solving the nonlinear Schrodinger equations with the split-step method while the SOA is simulated with two different models that we show to be in a good agreement, transmissions over distances of the order of several hundreds of kilometers are shown to be possible, and very long distances can be reached especially if in-line sliding filters are used     

Information-Theory Analysis of Skewed Coding for Suppression of Pattern-Dependent Errors in Digital Communications

We present information-theory analysis of the tradeoff between bit-error rate improvement and the data-rate loss using skewed channel coding to suppress pattern-dependent errors in digital communications. Without loss of generality, we apply developed general theory to the particular example of a high-speed fiber communication system with a strong patterning effect     

Optimisation of two-stage Raman converter based on phosphosilicatecore fibre: modelling and experiment

Parameter optimisation of a two-stage Raman converter based on phosphosilicate-core fibre is presented. The optimal operational regime is determined and its tolerance against variations of laser parameters is examined. Results of numerical modelling are in a good agreement with experimental data     

Generalized root-mean-square momentum method to describe chirpedreturn-to-zero signal propagation in dispersion-managed fiber links

We present a generalized momentum method to describe evolution of the root-mean-square (rms) (averaged over time) optical pulse characteristics in dispersion-managed fiber lines. A closed system of the ordinary differential equations is derived for the rms pulse power, width, and chirp. The developed method can be useful for massive numerical simulations required to optimize wavelength-division-multiplexing dispersion-managed transmission using chirped return-to-zero format