Design equations of flat top Super Structured Fibre Bragg Gratings for WDM-coherent direct sequence OCDMA

In this paper, we present a Super Structured Fiber Bragg Grating (SSFBG) en/decoder with rectangular square global envelope for the implementation of Coherent Direct Sequence OCDMA systems over WDM channels using a single device. It presents a periodic spectral pattern and a flat top a broadband spectral envelope that can be employed for en/decoding multiple sub-bands simultaneously with identical insertion loss. We present the design equations in which we include the fabrication characteristics such as the width of the UV illumination beam and the fabrication sampling. We also show two fabricated devices that show the feasibility of the technique.