OXC

A network device used to switch high-speed optical signals (e.g., SDH/SONET OC-3, OC-12, and OC-48). An OXC can switch the signal in its entirety, or can demultiplex it and switch its component signals. For example, an OXC can receive an OC-48 signal and demultiplex it into four constituent OC-12 signals, each of which it forwards through a separate OC-12 port. An opaque OXC is essentially a digital cross-connect (DXC) employed in an optical system. This approach requires that the optical signal be converted into electrical format before being switched by the electronic DXC, then converted back into optical format before being placed back on the fiber optic transmission system (FOTS). This optical-electrical-optical (OEO) signal conversion process adds some amount of delay to the signal, but offers the advantage of signal regeneration to deal with issues of signal dispersion and attenuation. A transparent OXC, also known as a photonic cross-connect (PXC), is characterized as optical-optical-optical (OOO), as it performs the switching function without converting the signal to electronic format. This approach does not impose the same level of signal processing delay as the OEO process employed in an opaque OXC, but neither does it provide signal visibility. In other words, it is not possible to monitor the signal quality or determine the nature of the higher layer protocols employed. A translucent OXC is a hybrid that includes both optical and electronic switching modules and operates in both opaque and transparent mode. If signal visibility or regeneration is desirable, the electronic module is employed. See also attenuation, cross-connect, dispersion, DXC, OC-3, OC-12, OC-48, OEO, OOO, optical, protocol, regenerator, SDH, signal, and SONET.