Z. Bakonyi

Dissipative solitons and their critical slowing down near a supercritical bifurcation

The existence of a novel kind of soliton in dissipative systems with competing, noninstantaneous nonlinearities has been predicted and experimentally verified. These subcritically bifurcating solitons exist near a supercritical continuous wave bifurcation. We show that their peculiarities originate from different saturation behavior of nonlinear loss and gain with regard to power and energy. Branches of stable and unstable solitary waves have been identified. For the first time to our best knowledge, we have experimentally proved critical slowing down of solitons.

Optimization of signal transmission by an in-line semiconductor optical amplifier-saturable absorber module

A module consisting of a semiconductor optical amplifier and a saturable absorber is investigated with respect to gain, pulse and noise dynamics and their dependence on device parameters. Based on the analytical and numerical results optimization strategies were found regarding high-bit-rate signal transmission. The results are compared with recently reported experimental data.

In-line saturable absorber in transmission systems with cascaded semiconductor optical amplifiers

A significant improvement of high bit-rate RZ transmission system performance was demonstrated by employing an in-line saturable absorber. The basic features of such a system are discussed. Error free 5-Gb/s single channel transmission over 30000 km has been obtained at 1.3-/spl mu/m in a fiber loop setup. The saturable absorber was fabricated directly in the semiconductor optical amplifier by ion-implantation.

Noise suppression by saturable absorber in transmission systems with semiconductor optical amplifiers

Summary form only given.Semiconductor optical amplifiers (SOA) are a cost-effective solution for high bit-rate communication systems provided that the growth of amplified spontaneous emission (ASE) can be controlled by using e.g., 2R regenerators. A very economic way to distributed regeneration is to fabricate a saturable absorber (SA) layer by ion implantation of one of the SOA chip facets. Such devices have been used in mode-locked lasers and have been shown to be an effective tool for noise suppression in 1.3 /spl mu/m transmission systems with in-line SOA. In this contribution we identify the principal effects which lead to ASE growth suppression, present results on optimization of such system and report an essential performance improvement, especially when a gain clamped SOA has been used.

Modulational instability in a transmission system with semiconductor optical amplifiers and in-line filters

Modulational instability of continuous waves in transmission systems with semiconductor optical amplifiers and in-line filters was theoretically and experimentally analyzed. Stable and unstable domains were identified. Even in the normal-dispersion region, modulationally unstable domains can exist for an appropriate filter detuning.

Quantum dot (InAs/InGaAs DWELL) semiconductor optical amplifier

In this paper, InAs/InGaAs quantum dot SOA emitting at greater than 1300 nm with gain as high as 18 dB at low with 100 mA pump current was designed and manufactured. The gain recovery dynamics of the QD-SOA sample was studied using a pump-probe set up. Extremely low linewidth enhancement factor and fast gain recovery make the device perspective for deployment in communication systems. The position of the gain peak and the bandwidth are practically temperature independent.