Direct design of multichannel fiber Bragg grating with discrete layer-peeling algorithm

The conventional sampling approach fails when the seed grating contains phase shifts because this approach is based on the resonant coupling principle, which explains the multichannel spectrum formation but does not provide an accurate solution. We use the discrete layer-peeling algorithm for directly synthesizing the multichannel grating. The new method restores the channel distortion in the sampled grating, resulting in uniform reflection and dispersion spectrum channels. We introduce further an optimized set of channel phases, such that the maximum reflective index modulation required for N channels is only ... N times that for the single channel.