Fiber gratings as demultiplexing filters for WDMA networks

Fiber gratings written into photosensitive fiber by UV holographic techniques are attracting considerable attention due to their broad range of potential application in photonic devices and optical communications. Parallel to the efforts in the optimisation and refinement of the fabrication procedures, research efforts have been directed towards several applications such as dispersion compensation, and sensors. Being an optical filter, the fibre grating (FG) can also be applied as a demultiplexer in OFDM high-speed communication systems. The feasibility of this approach is contingent on: a) the possibility of a wide range of wavelength tuning, and b) the obtention of filter bandwidths in the order of those corresponding to the transmitted channels (few GHz). In this paper, we report the results on an crosstalk analysis carried out to determine the performance of these structures as demultiplexers in direct detection ODFM communication systems. We show that they have the potential of providing significant improvement in terms of bit error rate (BER) as compared to fibre single cavity Fabry-Perots (SCFP)