Two Multi-dimensional Ocdma System

Optical code multiple access(OCDMA) communication system is a spectral spreading system. All users in the system share all the bandwidth in the same time. Because of the using of the almost infinitude bandwidth in the fiber, OCDMA system will become more and more important in future ultra-high speed LAN and online computer communication system. But at present, the researches for OCDMA need to go more deep into.In this article, two- and three-dimensional(2-D and 3-D) OCDMA system are researched. In 2-D OCDMA system, the code sequence for each user is spreaded in time chip and wavelength, or in time chip and space, or in wavelength and space. 2-D OCDMA system has good performance compared with one-dimensional(1-D) OCDMA system because of the increasing of one dimension. In 3-D OCDMA system, the code sequence for each user is spreaded in time chip, wavelength and space. Compared with 2-D OCDMA system, 3-D system can accommodate more total users and simultaneous users.The basic theory, system scheme and key technology of OCDMA technology are introduced in the first chapter. The advantages and the future development of OCDMA system.are summarized.The different kinds of 2-D and 3-D OCDMA systems are introduced in chapter two. Their system constructures and bit error rates are analysised We can point out that 2-D and 3-D OCDMA system will become an important developing direction.In the third chapter, the properties of the bipolar sequence are analyzed firstly. The auto-correlation, the cross-correlation and the accommodation of simultaneous users under given bit error rate between the bipolar codes and unipolar codes are compared. The conclusion is that bipolar codes have better auto-correlation and cross-correlation, and the system that uses bipolar codes can accommodate more users and simultaneous users. So the bipolar codes are...