Abstract: Non-tracking solar collector device (1) comprising at least an absorber element (2), at least a couple of reflector elements (3) disposed on opposite sides of the absorber element (2) for conveying the solar radiation onto the absorber element itself and said reflector elements (3) comprising at least one fixed portion (8a,8b) and at least one rotating portion (9); the rotating portions (9) being movable between at least a first extreme position (10), in which the rotating portions are moved away from each other and the entire surface of said reflector elements (3) is substantially continuous, and a second extreme position (11), in which the rotating portions are moved close to each other in order to substantially obscure said absorber element (2).

Abstract: Non-tracking solar collector device (1) comprising at least an absorber element (2), at least a couple of reflector elements (3) disposed on opposite sides of the absorber element (2) for conveying the solar radiation onto the absorber element itself and said reflector elements (3) comprising at least one fixed portion (8a,8b) and at least one rotating portion (9); the rotating portions (9) being movable between at least a first extreme position (10), in which the rotating portions are moved away from each other and the entire surface of said reflector elements (3) is substantially continuous, and a second extreme position (11), in which the rotating portions are moved close to each other in order to substantially obscure said absorber element (2).

Abstract: The present invention provides a planar optical waveguide amplifier for amplifying optical communications signals when optically pumped by radiation of a pumping wavelength, the amplifier comprising: an optical buffer layer formed on a substantially planar substrate; an optically-transmissive metal-oxide-based waveguide core formed on the buffer layer, the core comprising aluminium oxide and a gain medium; and an optical cladding layer formed over the core. Preferably, the composition of the core predominantly comprises aluminium oxide and the gain medium comprises erbium and/or ytterbium. The waveguide core can be formed by reactively dc sputtering aluminium. The invention has the advantage of allowing higher erbium doping concentrations than is possible for silica-based amplifiers.

Abstract: The present invention provides a planar optical waveguide amplifier for amplifying optical communications signals when optically pumped by radiation of a pumping wavelength, the amplifier comprising: an optical buffer layer formed on a substantially planar substrate; an optically-transmissive metal-oxide-based waveguide core formed on the buffer layer, the core comprising aluminium oxide and a gain medium; and an optical cladding layer formed over the core. Preferably, the composition of the core predominantly comprises aluminium oxide and the gain medium comprises erbium and/or ytterbium. The waveguide core can be formed by reactively dc sputtering aluminium. The invention has the advantage of allowing higher erbium doping concentrations than is possible for silica-based amplifiers.