Bruno Costa

Semiconductor devices for photonic switching

The concept of all optical networks and the motivations for investigating them are briefly mentioned. Photonic switching is specifically considered and reasons for carrying out research on semiconductor based materials and devices for the implementation of optical switching functions are given. Afterwards the main physical properties that may find applications in photonic devices made of semiconductor materials are reviewed, with emphasis on QW structures and the associated important phenomena of Quantum Confined Stark Effect and Optical Stark Effect. The state of the art is then presented regarding the various devices needed in a photonic switching node: space/time switches and switching matrices (both of the electro-optical and opto-optical type), frequency switches, frequency converters and filters, digital memory elements made by optical bistable devices, logic optical devices.

Optical Fibre System and Related Sources

Optical fibres are finding increasingly widespread use in all telecommunication applications. Industrially developed countries have plans for installation of thousands of kilometers of optical cables in the near future. Technical advantages of optical fibres are the justification for this success: low attenuation, high bandwidth, low weight and small size, insensitiveness to e.m. disturbances, suitability for a large range of applications, easy upgradability. Applications include intra building and intra vehicle communications, local area distribution (links between computers), subscriber loop, links between telephone exchanges, inter city, long distance communication, submarine cables.