4D encoding scheme for OCDMA system based on multi-diagonal code

Abstract

This study represents four dimensions (polarization/spectral/temporal/spatial) encoding scheme for the multi-diagonal (MD) code implementation in an incoherent system, using a direct detection technique. In the proposed scheme, the spectral/temporal/spatial encoding is incorporated with polarization encoding as a fourth-dimension signature of MD code. The coder and decoder are based on polarization beam splitters, fiber bragg gratings, delay lines and star couplers. Spectral/temporal/spatial MD code is employed as the signature allocated to an individual horizontal or vertical state of polarization. The results indicate that the proposed scheme can be used for the high-speed transmission. Also, its performance capacity overpasses the existing codes. Hence, the proposed system enhances 1.5, 2, 2.16, 2.63 and 5.7 times the number of users of the systems based on three dimensional dynamic cyclic/ multi-diagonal (3D-DCS/MD), three-dimensional multi-diagonal (3D-MD), three dimensional perfect difference/multi-diagonal (3D-PD/MD), three dimensional perfect difference (3D-PD) and two dimensional multi-diagonal (2D-MD) systems, respectively.