Master Thesis - 2008

The tera-bit order capacity of ultrahigh-speed and wide-band networks will become necessary to provide highly advanced multimedia services. In conventional networks, electronic circuits limit the speed capability of the networks. Consequently, all-optical networks are essential to realize ultrahigh-speed and wide-band communications. All-optical networks require self-routing principles, because realizable functions of optical devices cannot perform complicated current networks.

As for optical multiplexing methods, the time division multiplexing (TDM) and the wavelength division multiplexing (WDM) methods have mainly been studied. Moreover, even if both TDM and WDM technologies are adopted, the realizable multiplexing capacity is insufficient. On the other hand, the optical code division multiplexing (CDM) method has drawn researchers' attention. The photonic switch based on CDM was reported, however, there are very few reports that consider its application to large-sized public networks.

In this paper, we propose the configuration of an all-optical CDM switching network and the packet assembly method based on self-routing principles. We also illustrate one of network architectures where the proposed switching fabric can be exploited.

To evaluate the multiplexing performance, we demonstrate the maximum number of channels under an error-free condition and the BER characteristics when the Gold sequence is applied as one of the CDM code sets, and show that the network of the sub-tera-bit order capacity is realizable by adopting TDM, WDM and CDM technologies.