1x16 demultiplexer using volume holographic gratings in iron-doped lithium niobate

A novel photorefractive demultiplexer for dense wavelength division multiplexing (DWDM) applications has been experimentally demonstrated for the first time, by using the narrow-band filtering and demultiplexing properties of a volume holographic gratings formed in lithium niobate crystal. For the multiple recording of the 16-wavelength channels with equal diffraction efficiency, the rotation multiplexing and the exposure time schedule are used. The 1x16 photorefractive DMUX is designed to work with a channel spacing of 0.5nm range from 670nm to 677.5nm and a bandwidth of 0.16nm. From the experimental results, the measured diffraction efficiency of each channel is 8.3+/- 0.62%. The 3dB bandwidth of 0.16+/- 0.005nm and the channel spacing of 0.46 approximately 0.5nm, with optical loss from Fresnel reflection and absorption in the crystal of 2.22dB/cm, are measured.