Using the simple inverse Fourier transformation(FT), the index modulation structure with the sampled period for the sampled fiber Bragg gratings was designed. In this method, the enable channels are operated at identical wavelength while the unable channels are almost suppressed completely. The enable and unable channels can be established based on the applications. This technique is very useful to design the optical devices such as optical add and drop multiplexers (OADMs), and interleavers with dispersion and dispersion slope compensation.