Optical Overlapping PPM-CDMA Systems with Novel Two-Dimensional Optical Codes

Utilizing the hybrid-coding method on both existing two-dimensional (2D) codes and one-dimensional (lD) optical orthogonal codes (OOCs), novel 2D optical codes are systematically constructed, and applied to optical code-division multiple-access (CDMA) systems with the use of overlapping pulse position modulation (OPPM) technique in this paper. The novel optical OPPM-CDMA system not only can enhance the system confidentiality, compared to the traditional optical CDMA system adopting on-off keying (OOK) technique, but also can further improve the transmission data rate and spectral efficiency due to utilizing OPPM technique instead of the PPM technique.