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We demonstrate the fabrication of a waveguide hologram and describe how a plane-wave output beam can be generated for the illumination of a finger for fingerprint image capture. Also, when using a diverging beam in the substrate as a reference wave, one obtains a set of gratings written in the hologram. The reflected light from the finger is spatially filtered by this hologram, providing bandpassed information back through the waveguide when it is viewed through the plate.

High channel density broadband wavelength division multiplexers (WDMs) based on periodic grating structures are discussed. These so-called single-window WDMs transmit a large number (> 100) of independent wavelength channels through a single fiber and within a single fiber communications window in both singlemode and multimode fiber cases. In this paper, singlegrating WDMs are analyzed in the context of the fundamental relation between channel density, crosstalk, power budget, and diffraction limited beam propagation. Also, the practical aspects of WDM-based fiber optic networks for high-speed (broadband) multi-media communication are discussed.

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