Volume holographic wavelength demultiplexer based on rotation multiplexing in the 90° geometry

A novel photorefractive wavelength demultiplexing scheme for optical communications and spectroscopy applications has been proposed and experimentally demonstrated for the first time, by using the narrowband filtering and demultiplexing properties of volume holographic gratings formed in LiNbO3:Fe crystal. The holographic gratings are superimposed in the crystal with rotation multiplexing in the 90 degrees geometry. In this scheme, the center wavelength and orientation of the grating for each channel are simply changed by rotating the crystal with respect to the crystal axis without changing the recording angles, To verify the proposed scheme we have designed the 16-channel demultiplexer with a 3 dB spectral bandwidth of 0.16 mn and a channel spacing of 0.5 nm in the wavelength region of around 670 mn. Some preliminary experimental results are presented and discussed. (C) 2001 Elsevier Science B.V. All rights reserved.