Wavelength switching technologies and requirements for agile optical networks at line rates of 100 Gb/s and beyond

Future optical networks will have to support DWDM line rates beyond 100 Gb/s and transport data with much higher spectral efficiency than today’s networks, so as to meet the rapidly increasing demand for transmission capacity. At the same time, these networks need to provide increased flexibility at the optical layer to allow fast and automated provisioning of capacity wherever and whenever it is demanded. In this contribution we describe the different requirements that such high-speed agile optical networks pose on wavelength-selective switches and ROADM node architectures and then discuss the technology options that are available for building next-generation wavelength switching nodes.

► We examine the requirements for next-generation wavelength-selective switches.
► Improved pass-band shape and higher stop-band attenuation required at 100 Gb/s.
► Support for flexible width pass- and stop-bands desired for channels above 100 Gb/s.
► Increased number of ports needed for colorless and directionless add/drop switching.
► Most promising: LCoS-based switch engines and “route-and-select” architectures.