Implementation of 3-D Optical CDMA Networks with Double Balanced Detection

This study proposes novel three-dimensional (3D) matrices of wavelength/time/spatial code for code-division multiple access (OCDMA) networks, with a double balanced-detection mechanism. We construct 3D carrier-hopping prime/modified prime (CHP/MP) codes by extending a two-dimensional (2D) CHP code integrated with a one-dimensional (1D) MP code. The corresponding coder/decoder pairs were based on fiber Bragg gratings (FBGs) and tunable optical delay lines integrated with splitters/combiners. System performance was enhanced by the low cross-correlation properties of the 3D code designed to avoid the beat noise phenomenon. The CHP/MP code cardinality increased significantly compared to the CHP code under the same bit-error rate (BER). The results indicate that the 3D code method can enhance system performance because both the beating terms and multiple-access interference (MAI) were reduced by the double balanced-detection mechanism. Additionally, the optical component can also be relaxed for high-transmission scenery.