Wavelength Selective Switching components are industrial packages integrating devices for wavelength multiplexing/demultiplexing of WDM signals and mechanisms to switch signals on a per-wavelength basis. Multiplexing/demultiplexing elements can be realized as array waveguide gratings (AWG). Currently, the two major switching technologies are microelectromechanical systems (MEMS) and liquid crystals (LCoS).
A WSS component is characterized by the number of WDM channels (e.g., 40 or 80) and by the number of selectable directions (e.g., 1x5 or 1x9). The main application of WSSs is the implementation of reconfigurable optical ADMs (ROADM), or, in full mesh arrangements, of optical cross-connect systems.
Reflective MEMS:
JDS Uniphase http://www.jdsu.com/ProductLiterature/wsscomp_wp_cms_ae.pdf
Capella http://www.google.com/patents/about?id=0UV9AAAAEBAJ&dq=RE39411
Reflective Slit MEMS:
Nistica http://www.google.com/patents/about?id=s6OsAAAAEBAJ&dq=nistica
Transmissive Liquid Crystal:
Oclaro http://oclaro.com/WSS_liquid_crystal.php acquired from Xtellus http://www.xtellus.com/liquid_crystal.htm
Reflective Liquid Crystal on Silicon:
Finisar http://www.finisar.com/download_yVzRcEWSS%20ROADM%20Product%20guide_FINALDec08.pdf Acquired from Optium http://www.lightreading.com/document.asp?doc_id=154135 which acquired it from Engana http://www.lightreading.com/document.asp?doc_id=90138
Liquid Crystal:
CoAdna http://www.coadna.com/index429f.html?page=lightflow
Silica-on-Silicon Grating:
Enablence http://www.google.com/patents/about?id=LqF9AAAAEBAJ&dq=enablence+MUX
Unsure of Technology:
neophotonics http://www.neophotonics.com/product/detail.php?id=58 (Most Likely MEMS but can not find reference of this)