Abstract
We report the development of a lab prototype for all optical synchronization at 10GHz. Adjusting the distance between the AR coated facet of the MQW semiconductor laser and the ferrule it was possible to induce the self-pulsation needed for correct operation. In the presence of optical RZ signals, the device leaves is natural pulsation frequency synchronizing with the input data.

Abstract
We report the development of two lab prototypes for all optical clock recovery and optical synchronization, composed by a DFB semiconductor laser driven by a ultra-fast switching current circuit. It was verified that a fast switch of the laser bias current accomplished by the strong feedback in the external cavity induce the self-pulsation needed for correct operation. In the presence of optical RZ signals, the device leaves is natural pulsation frequency synchronizing with the input data.

Abstract
This paper summarizes the research activities of the optical communications group at University of Aveiro and Institute of Telecommunications - Aveiro pole. Several activities like clock recovery systems, both electrical and all optical, electrical equalizers for very high bit rate DST systems, post-detection filters for multigigabit optical receivers, soliton systems, simulation work on WDM, DST, EDFA and short pulse generation for high bit rate systems are presented.

Abstract

Abstract

Abstract
An investigation on optical amplification in Ti waveguides in LiNbO3 doped with Er ions by thermal diffusion of thin metallic stripes is presented. The possibility of fabricating efficient optical amplifiers in LiNbO3 substrates realized by localization of the dopant on surface areas of the crystals was theoretically evaluated and the feasibility of fabricating efficient amplifiers in such doped structures was experimentally verified. It was concluded that the localized doping technique allows optimization of amplifier performance through adjustment of the active region geometry to the mode intensity profile.