Giorgio Grasso

23 dBm output power Er/Yb co-doped fiber amplifier for WDM signals in the 1575-1605 nm wavelength region

We report, for the first time to our knowledge, theoretical and experimental results concerning a broadband and gain-flattened Er,Yb-codoped double-cladding-fiber amplifier, which provides up to 23-dBm output power in the wavelength region 1575 nm to 1605 nm.

Optical switching technologies and their applications

In this paper system applications, geometry, physical effects and materials of optical switching devices are reviewed. Main system scenarios are presented and some key features such as size, loss, speed, scalability and granularity are highlighted. Two principal categories of optical switches are considered, i.e. guided-wave switches and free-space switches. In the first category some sub- classes have been identified according to their geometrical configuration, principle of operation and, then physical mechanism and materials. As for the geometry, the most frequently used configurations are briefly described together with their advantages and disadvantages. Different physical effects suitable to obtain the index change, which the switching function is based on, are also described with reference to the material substrates. Switches based on semiconductor optical amplifier gate are also analyzed. In the free-space category the main sub-classes are represented by the opto-mechanical devices and micro-opto-electro- mechanical systems switches. The last technology combines the free-space interconnecting with the integration capability on a single silica chip. The main advantages such as the ability to scaling up to large switch fabric and some issues such as packaging and reliability are analyzed. Finally, devices based on polarization change, acousto- optics interaction, total internal reflection and holography are illustrated.