Our proposal adds an arrayed waveguide grating (AWG) operated at 1.5 mu m to the star coupler of a passive optical network (PON) in the remote node (RN) and separates the original PON and the overlay via 1.3/1.5 mu m splitters, which guarantees the maintenance function

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The aim of this study was to analyze and evaluate the oral mucosa and the surface constitution of dental materials to display the characteristics and the behaviour of dental composites concerning the margin fit. Therefore, the gingiva and composite restorations of 45 patients aged 17-69 years were examined with a new digital confocal laser scanning microscope developed in Rostock. The device works in contact with the surface of the examination region using a water immersion objective and a diode laser with a wavelength of 670 nm. As a result of a PMMA-Cap with a thickness of 0.5 mm, we can create images with exact depth information and of very good quality. The epithelium of the gingiva with its cellular and subcellular structures could be observed up to a depth of 200 microm. Also, papillary crests, blood vessels and even the blood flow were visible. An inflammation of the gingiva could be verified because of the existence of inflammatory cells. The enamel and dental restorations could be observed up to a depth of 80 microm and allowed the evaluation of the margin fit. Confocal laser scanning microscopy seems to be suitable for the non-invasive examination of oral mucosa and dental materials in vivo.

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The all-optical transparent interconnection of two experimental OFDM-LANs is demonstrated. Fiber amplifiers are used to compensate network losses. Each LAN is equipped with four fully engineered, microprocessor- controlled, absolute frequency stabilized subscriber stations. The interconnection is realized utilizing a full duplex star coupler as central node. A proposal to extend the realized network for frequency re-use is given

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