Network applications of cascaded passive code translation for WDM-compatible spectrally phase-encoded optical CDMA

Recently, there has been a renewed interest in optical code-division multiple access (OCDMA) due to its potential for offering increased levels of security at ultrahigh data rates as well as for simplifying key networking functions, such as replacing (active) wavelength translation with cascaded passive all-optical code translation (CT). Much of the research done in this area has focused on homogeneous OCDMA networking, where it is assumed that the fiber bandwidth is used only for OCDMA signals. In contrast to other proposed OCDMA systems, we have developed a novel narrowband (NB) spectrally phase-encoded (SPE) OCDMA that is compatible with existing transparent reconfigurable dense-WDM (DWDM) networks and has high spectral efficiency. In this paper, we experimentally demonstrate, for the first time, the feasibility of multistage CT in the proposed WDM-compatible SPE OCDMA system, and we also describe how cascaded CTs can play a central role in ring- and star-network architectures. Specifically, we describe a star-network architecture in which both unicast and multicast interconnections among ends are passively "routed" by means of such cascaded CTs, a ring-network architecture in which CT and fast optical switching enable a code-based equivalent to add/drop wavelength multiplexing, and a shared code-scrambling application for increased signal obscurity.