Reduction of Linear Crosstalk Over Waveguide-Grating-Based Optical CDMA Coders/Decoders

A compact optical code-division multiple-access (OCDMA) network coder-decoder (codec) with a crosstalk reduction mechanism is proposed. The transmitter-receiver codec is constructed using cascaded dual arrayed-waveguide gratings (AWGs) that generate a pure crosstalk term, referred to in this paper as a pilot signal. The pilot signal is multiplied by an appropriate gain such that its intensity is equal to that of the crosstalk noise and is then subtracted from the desired user signals in order to eliminate the accumulated beat noise completely. The simulation results show that the proposed scheme eliminates the in-band crosstalk beat noise and achieves a larger eye diagram than codecs with no crosstalk reduction capability.