Realization of orthogonal codes in optical information processing

Abstract

Spread spectrum (SS) has proven to be an efficient transmission scheme due to its antijamming and interference reduction capability. In multiuser environment, users are assigned distinguishable unique codes with low cross correlation (CC) values among each other. Walsh-Hadamard codes are an important class of spreading codes that allow construction of long sequences with desired cross correlation values. Optical realization of Walsh-Hadamard codes becomes important for optical code division multiple access (CDMA). Design needs the use of nonlinear optics capable of handling multivalued signal. To this aim, this paper proposes an all-optical design of Walsh-Hadamard codes that exploit the polarization properties of light.