Dense wavelength division multiplexing (WDM) systems require narrowband wavelength filters for simultaneous multiplexing/ demultiplexing of several channels. We report on a concept of demultiplexing of two channels (channel spacing 0.8 nm) by Bragg diffraction from two thermally fixed volume-phase reflection holograms in photorefractive lithium niobate crystals doped with iron. More than 25dB crosstalk suppression is achieved, and intensity losses are only between 2.3 and 5.2dB. A compact demonstrator was built to illustrate the aplicability of this WDM-concept. The insertion losses amount only between 5.2 and 5.9 dB.
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