10 Gb/s transmission performance of cascaded group-delay-flattened fiber Bragg gratings

For the purpose of applying 10 Gb/s DWDM systems, the group-delay-flattened FBGs, which have both square spectral response and linear phase response, are developed. The conventional FBGs have the large group delay variation in the reflective bandwidth, and the accumulation of the dispersive effects is serious problem in cascading. On the other hand the group-delay-flattened FBGs has linear phase response, and the power penalty in cascaded 5 FBGs is under 0.1 dB independently of wavelength. These results confirm that the group-delay-flattened FBGs reflect the 10 G/s signals keeping the original waveform well. It therefore results that the group-delay-flattened FBGs are suitable for ADM used in 10 Gb/s DWDM optical transmission system, and these FBGs may be ideal devices for more complicated DWDM network systems.