Introducing wavelength granularity to reduce the complexity of optical cross connects

In future transport networks, optical cross connects (OXC´s) could optically route wavelength-division-multiplexed (WDM) signals. In order to switch a large amount of channels, OXC´s should have much more complex structures, in terms of both optical components and internal controls. To cope with this, we propose to introduce optical granularity: if WDM signals with the same source-destination pair were assigned a group of adjacent wavelengths, they could be optically routed by OXC´s as a single channel. This modifies usual routing and wavelength assignment, but reduces the number of optical components in OXC´s and also makes it easier to configure and modify connections. Advantages are similar to those that might come from increasing electrical granularity (i.e., using fewer signals with a higher bit rate), if this option were not limited by transmission impairments.