On the theory of self-similar parabolic optical pulses

Self-similar optical pulses (or “similaritons”) of parabolic intensity profile can be found as asymptotic solutions of the nonlinear Schr¨odinger equation in a gain medium such as a fiber amplifier or laser resonator. These solutions represent a wide-ranging significance example of dissipative nonlinear structures in optics. Here, we address some issues related to the formation and evolution of parabolic pulses in a fiber gain medium by means of semi-analytic approaches. In particular, the effect of the third-order dispersion on the structure of the asymptotic solution is examined. Our analysis is based on the resolution of ordinary differential equations, which enable us to describe the main properties of the pulse propagation and structural characteristics observable through direct numerical simulations of the basic partial differential equation model with sufficient accuracy.

Optical communications applications of ultra-long Raman fiber lasers

Recent work on ultra-long Raman fiber lasers has shown that it is possible to create quasi-lossless transmission conditions in fiber spans long enough to be considered for high speed optical communications. This paper reviews how quasi-lossless transmission conditions are reached and presents experimental results of 40Gb/s transmission in a quasi lossless system. The performance is compared with a conventional EDFA based system.

Normal dispersion fibre-enhanced nonlinear optical loop mirror for 2R regeneration and phase margin improvement

A novel all-optical regeneration technique using loop-mirror intensity-filtering and nonlinear broadening in normal-dispersion fibre is described. The device offers 2R-regeneration function and phase margin improvement. The technique is applied to 40Gbit/s return-to-zero optical data streams.

2R and 3R optical regeneration in 40 Gbit/s WDM terrestrial networks

We analyse a 2R regenerator using nonlinear-optical-loop-mirror and a 3R regenerator employing nonlinearly-enhanced amplitude modulator in 40Gbit/s WDM networks based on standard fibre (SMF). Characterization of one- (600km of SMF) and two-step regeneration is presented.