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Optical Code Division Multiple Access coder/decoder pairs based on temporal optical pulse shaping with fiber Bragg Gratings and electrooptic modulators

This paper presents recent proposals that have been made in the field of optical pulse shaping techniques based on the space-time duality, with an especial attention to their application for the design of encoder/decoder pairs in all-fibre Optical Code Division Multiple Access (OCDMA) systems. Two different proposals are presented, one based on an Optical Fourier Transformer using a dispersive media and the other based on the temporal self-imaging effect. Fiber Bragg Gratings are used as dispersive elements and electro-optic modulators for the amplitude or phase coding, allowing the electrical reconfiguration of the codes. Experimental results, both for coherent and incoherent schemes, are shown for the two systems transmitting at data rates of 1.25 Gbps and 10 Gbps respectively with a fixed codification rate of 10 Gcps and using a subset of the Hadamard codes with a length of 8 chips.