Conventional Fixed-Grid ROADMs

The wavelength selective switch (WSS) is the core building block for ROADM architectures in agile optical networks. It provides the flexibility to remotely provision, multiplex, and adjust power for any and all wavelengths at a network node—simplifying planning and provisioning, streamlining inventory management, and accelerating time-to-service.

While next-generation networks will require TrueFlex® capabilities, the current generation is built largely upon the fixed-grid WSS, optimized for 48-channel or 96-channel DWDM networks with predominantly 10 G channels. With more units shipped than any other supplier, JDSU has led the market through multiple generations with its liquid-crystal (LC) wavelength blocker, planar lightwave circuit (PLC) ROADM, and micro-electromechanical systems (MEMS) technology.

A fixed-grid WSS module is typically used in a broadcast-and-select node architecture in combination with arrayed waveguide grating (AWG) filters for terminating traffic associated with each “degree” of the node (for example, connecting to an inter-office fiber link). Each WSS is a 1xN-port device, typically paired with an optical splitter in each degree, where the N ports combine wavelengths being added at a node with those expressing through from other directions. Each wavelength can be dynamically attenuated to be switched and power balanced for optimal performance.

The “Mini” series WSS is based on the highly-successful JDSU free-space optics platform with a MEMS switching engine. This provides high-performance routing and attenuation control in a compact footprint.