ABSTRACT
The huge potential of optical networks for satisfying the skyrocketing needs of broadband telecommunications services while meeting rigid quality of service requirements has long been acknowledged. However, although fiber has become the medium of choice in telecommunication networks, its vast resources are severely underused because of the much slower electronics that are interfaced with the optical medium. For instance, transceivers operate at speeds that are several orders of magnitude below the actual usable capacity of the fiber (several Gbps versus hundreds of Gbps). In order to achieve higher rates, wavelength division multiplexing (WDM) techniques have been widely suggested. The concept behind WDM is to partition the optical spectrum into multiple nonoverlapping λ channels, each assigned a wavelength and modulated at electronic speed. In parallel to WDM
transmission, recent studies have enabled the realization of photonic routing and switching devices that perform elementary functions such as wavelength routing and switching. With those devices in hand we can envision all-optical transparent networks that carry traffic between distant users on single beams of light from end-to-end. The optical network has the capability to route the signal on specified fiber paths, thereby allowing wavelength reuse, in addition to wavelength multiplexing. Furthermore, as in the radio frequency paradigm, sources can multicast signals to multiple destinations.
